One of the things high blood pressure sufferers talk about and feel bewildered about is why we recommend home monitoring of blood pressure to be done after they have rested.
Well, the truth is; checking your blood pressure after resting is the best way to get your true blood pressure reading.
Why…because a lot of positive things can happen to your blood pressure in those precious 5 minutes. The 5-minute rest allows time for your circulatory system to come to a rest. Doing so stabilises your blood pressure.
Not doing the at-rest blood pressure measurements means you have to consider the alternative. The alternative is 24 hours blood pressure monitoring. This is a continuous home blood pressure monitoring over a 24-hour period.
The secondary terminology for this pratice is ambulatory blood pressure monitoring.
What is ambulatory blood pressure monitoring and how is it done?
As the name implies, ambulatory blood pressure monitoring is a blood pressure monitoring system that measures the pressure inside your blood circulatory system outside of the clinical setting. Checking your blood pressure when you are ambulant.
Of course, the ambulatory blood pressure monitor will measure your blood pressure when you are active and inactive. For instance, when you are sitting on your sofa watching TV and when you are asleep too.
In short, ambulatory blood pressure monitoring checks your blood pressure regardless of whatever you are doing at fixed intervals. Fixed intervals BP checks could be every 30 minutes or much more frequently.
As long as you have the ambulatory BP monitoring attached to you, it will do its own thing whether you are active or inactive. Readings are certainly more accurate than wrist monitors.
Ambulatory blood pressure monitoring can be done over a longer time but usually ambulatory blood pressure takes readings over a 24-hour period.
The cuff of the ambulatory monitor is wrapped around your arm and the blood pressure reading device or meter is given to you along side it.
You go about your business during the day and night and at fixed intervals, the blood pressure cuff will inflate and deflate spontaneously to measure your blood pressure at that moment in time.
These readings are recorded digitally over the 24-hour period.
It helps if you can manually record your activities over the 24-hour period you have the ambulatory BP device on you. In particular, a timeline of your activities will help your doctor interprete the results a lot better.
There is evidence that ambulatory blood pressure monitoring provides lower blood pressure readings compared to clinic setting readings. That can make them desirable.
Who needs 24-hour ambulatory blood pressure monitoring?
Anyone with high blood pressure really, truth be told.
But it is not practical to use the ambulatory device on everyone. Don’t forget millions of people have problems with high blood pressure all over the world.
So, getting the device to everyone will be an expensive undertaking. Although the companies making the ambulatory blood pressure monitors will not complain.
That would be good business for them. But for now, with limited resources, it makes sense to strategically deploy the devices to those in whom the need is strongest.
Who are these people?
People for whom the need for 24-hour ambulatory moniring is strongest include:
Anyone with suspected wild blood pressure swings during the day
Individuals with suspected huge blood pressure rises at night
Someone with suspected sustained high blood pressure
If white coat hypertension is thought to be an issue
An individual who may actually have masked high blood pressure
Poor response to high blood pressure medications
Borderline high blood pressure individuals
A need for prediction of risk of blood pressure complications
Why is ambulatory blood pressure monitoring important?
In 2018, we woke up one morning in spring, with screaming headlines in 3 newspapers – The Times, The Daily Mail and The Telegraph, all UK Newspapers trashing the use of clinic blood pressure readings. The implication was that current methods were not just outdated but bordered on being unsafe.
Whilst the headlines may be true such as stated by Laura Donelly of the Telegraph:
“White coat syndrome is real, confirms a new study, showing blood pressure measurements taken by a doctor are 50 per cent less accurate than those taken at home. The research confirms theories that readings taken in a doctors’ surgery bear little relation to the true state of heart health”
It still doesn’t mean that we should throw away our regular blood pressure monitors used in hospitals and clinic settings because they are useless. These regular BP monitors still have a huge role to play in the diagnosis and management of high blood pressure.
For one, they are convenient to use and the digital versions are now widely available which means patients can actually monitor their blood pressure at home.
We should not underestimate the role of these new digital blood pressure monitors that are so easy to use. They only require very little training. Meaning patients can have an input into their high blood pressure management.
In any case, doctors hardly use one-time readings in clinical settings to make decisions anyway unless the reading is astronomically high. Even then the measurement needs to be repeated a couple of times before intervention is suggested.
By the way, these newspaper headlines were the result of a study that was published in the New England Journal of Medicine.
It’s a Spanish study that tracked the health of over 63,000 adults over 18 years of age. Over a 10-year period. They measured their blood pressure the usual standard way in the clinic and were given the 24-hour ambulatory blood pressure monitor to take home.
The monitors were set to record blood pressure at 20-minute intervals during the day and 30-minute intervals at night. The participant’s records were entered as valid and included in the study only if 70% of the readings included both systolic and diatolic.
What the researchers found:
They found out the ambulatory 24 hours blood pressure monitoring was a better predictor of cardiovascular death than one-time blood pressure readings in the clinic. This was particularly linked to 24-hour systolic blood pressure rises.
They also found that masked high blood pressure had the highest risk of death.
“In our study, unlike most previous studies, we observed consistently greater mortality associated with masked hypertension than with sustained hypertension, which might be due to the delayed detection of masked hypertension in patients, who consequently could have more organ damage and cardiovascular disease than patients with sustained hypertension”
Another thing is that we tend to be dismissive of white coat hypertension as nothing to worry about. Well, be careful of how quickly you reassure yourself or doctor reassures you.
Because white coat hypertension was associated with increased risk of death. Although not as high as masked hypertension.
By the way, masked hypertension are individuals who were thought to have normal blood pressure with the standard clinic blood pressure measurement techniques but in actual fact aren’t.
The net effect is silent damage to target organs. This exemplifies the ‘silent killer’ image of high blood pressure. You couldn’t make it up!
Some of the commonest questions that bothers peope with high blood pressure is; why do we measure resting blood pressure. Why don’t we measure blood pressure when we are active instead? Does resting blood pressure represent our true blood pressure?
I have lost count of how many times I have had to answer this question in our blood pressure forum. So, I felt it will be a good idea to write this resting blood pressure piece here.
That way I can just direct such enquiries here. Saves me writing the same response all the time.
And if you are not one of those people in that forum, well, you are in luck, because you will now know the answer in advance of other people.
Why do we measure blood pressure at all?
Before I delve into why resting blood pressure measurements are important, let me quickly talk about why we measure blood pressure at all in the first place.
May be we should start with the definition of blood pressure first.
What is blood pressure?
Blood pressure is an index of the pressure generated in the circulatory system during a cardiac cycle. A cardiac cycle includes when your heart ventricles contract and when the ventricles are relaxed. Ventricular contraction followed by relaxation represents one cycle.
Every time your heart contracts to push blood out of it into the circulatory system, there is a force behind it. That represents the systolic blood pressure. That is the top figure you see when you take your blood pressure reading.
In between the contractions (when the heart is relaxed) there is still some pressure within the circulatory system otherwise, blood flow will cease. That will not be compatible with life and as you know life has to go on.
The pressure within the blood vessels between those ventricular contractions represent the diastolic blood pressure. That is the bottom figure you see when you measure your blood pressure.
So, your blood pressure is a measure of the force or resistance within the circulatory system at that point in time.
Why should we bother measuring the pressure within the circulatory system? Why not let it do its own thing…
Why is it important to measure our blood pressure?
It is important to measure our blood pressure because it gives an idea of how much force the heart is generating with each pump and how much resistance there is in the receiving vessels downstream.
Measuring our blood pressure also provides us an ‘implied measure’ of the diameter (thickness) and elasticity of the walls of our arteries.
Because thicker arteries arenot very compliant to allow blood flow through them easily, hence diameter.
Inelastic arteries are also fairly resistant to free blood flow too.
Therefore thicker, inelastic blood vessels will give rise to higher blood pressure. The net effect is, the heart has to pump harder i.e work harder, to get blood through in that scenario.
Hence thicker, inelastic blood vessels will rebound on the heart, leading to enlarged heart with thicker muscle too. Ultimately leading to heart failure, if high blood pressure is undiagnosed and untreated for a long time.
Another complication of high blood pressure when the blood vessels have become thicker and inelastic is such vessels are prone to becoming narrower.
When blood vessels are narrower, they can become clogged up readily. This can lead to blood clots which can result in heart attack, stroke, vascular dementia, peripheral vascular disease and even kdney disease.
Why do we measure resting blood pressure?
From the above analysis, if you have high blood pressure, then your blood vessels are becoming thicker and inelastic. The higher your blood pressure is, the more inelastic your blood vessels have become.
Or put in another way, the higher your blood pressure is, the more the resistance they are putting up against free flow of blood.
These guidelines have recommended a resting time of between 3 minutes to at least 5 minutes before blood pressure measurement at home. Also make sure you are using an upper arm monitor as opposed to wrist monitor.
So, why do we recommend checking your blood pressure at rest?
Well, it’s very simple. Your blood pressure fluctuates throughout the day. In fact, whilst you are out and about, your blood pressure changes from minute to minute.
If I left my phone upstairs in the bedroom and I am downstairs in the living room and I hear my phone ringing and I rushed upstairs to get the phone, my blood pressure will change dramatically having done one flight of stairs very quickly.
Even if I went upstairs leisurely, my blood pressure will change. Heck, just talking on the phone answering the call, my blood pressure will change.
Worse still, if I was getting irritated over the phone by the attitude of my Energy Company’s Customer Service consultant because I have been mistakenly overcharged for my energy use in the last 3 months and he was fobbing me off, my blood pressure will hit the roof.
The point is; your blood pressure is affected during the day by all sorts of environmental and human factors like:
Emotional pain etc
With that in mind, it is better to measure your blood pressure at rest. Check your blood pressure when you have rested for those mandatory 3 – 5 minutes.
Those 3 – 5 minutes gives your body and your circulatory system an opprtunity to come to rest. Because measuring your blood pressure when those other factors are in play would give a skewed unreliable results.
A lot of those rises in blood pressure as a result of those environmental and human factors are temporary.
Temporary readings do not reflect your true blood pressure. Your at-rest blood pressure is a better reflection of your true blood pressure reading. Measure your blood pressure when the sea is calm before the storm begins.
A second point is this:
Your resting blood pressure is your baseline reading. Your starting point. Your best reading. Because we know that your blood pressure will change during the course of the day. That’s a fact.
So, if your resting blood pressure is normal, we don’t have to worry about what it does during the day as you go about your business.
Now imagine a scenario where your at-rest blood pressure is 190/135 mmHg. And we know that the only way is up once you are active.
Can you then imagine what could possibly happen with a blood pressure like that; if say that individual gets that customer service irritation or went out in the freezing cold winter weather or received some terrible news?
If that’s not a recipe for a heart attack or a stroke, I don’t know what is. This is an individual who needs attention. Urgently.
Compare that to someone else whose resting blood pressure is 125/70 mmHg. We know that barring something really calamitous happening to this individual, it’s unlikely his/her blood pressure rises during the day will do him/her any harm.
You should see your resting blood pressure as a baseline that either reassures us or tells us we need to do something…like adjusting your treatment. But of course, you need more than one reading.
In fact, there was a study that was carried out sometime ago that suggested the 5-minute resting rule before measuring blood pressure is not adequate.
The authors of this study are actuallly suggesting 25 minutes resting time before checking your blood pressure. In their study, the researchers found a steady decrease in both the systolic and diastolic blood pressure reading over the 25-minute period. A bigger decrease in systolic than diastolic.
This steady decrease in blood pressure was noted in all the study participants regardless of whether they were on blood pressure medications or not.
The researchers opined that the 5-minute resting blood pressure rule may be leading to over-diagnosis of hypertension and called for the resting time to be extended in the guidelines.
…because the minimal resting time before blood pressure measurement to obtain a stable Systolic Blood Pressure in 90% of the population is 25 minutes according to their research.
“Our study suggests that the current recommended practice of measuring Systolic Blood Pressure after 5 minutes of resting may not allow for adequate stabilization of SBP, which we find could take at least 25 minutes. Public Health Policies should take into account this result to organize the best way to diagnose hypertension in our societies and avoid overdiagnosis”
What is Ambulatory Blood Pressure Monitoring?
Now you know why we measure blood pressure at rest, I need to say a few words about ambulatory blood pressure monitoring. Because it sort of ties in with the concerns of those who feel their blood pressure should be measured in active periods instead of resting times.
The blood pressure machine will measure your blood pressure at fixed intervals and it’s recorded digitally. You may assist your doctor by writing down some of the activities you were engaged in during the day. That way your doctor can match the readings with the activities.
Indeed, the main concerns by individuals who feel that measuring blood pressure at rest is not ideal is because they feel that at-rest blood pressure reading mechanism is missing out on the blood pressure fluctuations that occur during the day and may be at night.
Valid concern…I must admit.
But for most people though, this is really not an issue if your blood pressure is well controlled. Even when your blood pressure is marginally elevated, those diurnal blood pressure fluctuations are not clinically significant.
In fact, this underscores why a good blood pressure control is important, if you have high blood pressure. Because you don’t have to worry about these diurnal blood pressure excursions, if your blood pressure control is good.
But there are circumstances where ambulatory blood pressure monitoring is indicated.
When is ambulatory 24-hour blood pressure monitoring necessary?
It may be wise to perform ambulatory blood pressure measurements in these individuals:
Anyone with suspected wild blood pressure swings during the day
Individuals with suspected huge blood pressure rises at night
Someone with suspected sustained high blood pressure
If white coat hypertension is thought to be an issue
An individual who may actually have masked high blood pressure
Poor response to high blood pressure medications
Borderline high blood pressure individuals
A need for prediction of risk of blood pressure complications
In all of those scenarios above, it may be wise to undertake 24-hour ambulatory blood pressure assessment. That way the right treatment strategy can be mapped out between you and your doctor.
Are wrist blood pressure monitors accurate? This is a question that I set about answering some years ago. Not out of medical research curiousity but as a patient myself.
Apart from knowing the answer to the accuracy of wrist monitors, I also explain why my answer is what it is and finally I’ll tell you if I recommend wrist BP monitors as a home blood pressure monitoring kit or not. That’s what you are going to get on this page.
Being a doctor and someone who suffers from high blood pressure, I accidentally found the answer to the question: are wrist monitors accurate for blood pressure; more out of luck rather than by design.
My curious search for an alternative to upper arm blood pressure monitor led me to discover the truth about wrist blood pressure monitors. The long and short of my short adventure was that the wrist blood pressure monitors are not accurate.
So, if you want to know the real answer to the question: are wrist blood pressure monitors measurements accurate? The answer is; No, wrist monitors are not accurate for blood pressure measurement.
My claim is based on my personal experience of 4 different brand of wrist monitors. These wrist monitors kept giving wild blood pressure readings. Usually BP readings that would suggest I am about to have a stroke or heart attack.
With doubts in my mind as to such ridiculously high readings, I had to do a validation of the readings. Fortunately I had an upper arm monitor at home.
When I checked my blood pressure with my upper arm monitor at the same time as the wrist monitor, I had normal blood pressure.
So, whereas the wrist monitor was producing BP readings that would suggest I needed to go to ER (A&E) immediately for medical attention, my upper arm monitor was giving readings that were perfectly normal.
The contrast between the wrist monitor and the upper arm monitor was as clear as the Biblical ‘Red Sea parting for Moses and his troops to go through’.
When you have recurrent episodes of false readings with different brands, it is not unreasonable to reach that conclusion that wrist monitors are not accurate for blood pressure measurements.
Mind you on each occasion, I validated with the upper arm monitor. Occasionally, there was a close match of the readings from the wrist monitor and the upper arm one.
But these episodes of the close match were very few and far between. Scenarios like that meant I had to reach that conclusion, that the wrist monitors were inaccurate and therefore unreliable.
Why are wrist blood pressure monitors not accurate for Blood pressure reading?
Okay I won’t just make a statement like that and not give you reasons for why wrist blood pressure monitors are not as effective as upper arm monitors.
One reason for this inaccuracy of blood pressure readings from the wrist monitors is the blood vessel from which the wrist monitor is getting its reading from.
Our body’s arterial tree is a high pressure system. But the walls of our arteries have been cleverly designed by nature to maintain a pressure gradient that drives blood onwards and forwards downstream.
This means smaller vessels are more muscular than larger vessels. Larger vessels closer to the heart are lot more elastic than smaller vessels downstream. The larger vessels have to be elastic to withstand the high pumping pressure of the heart ventricles.
Larger vessels – elastic
Smaller vessels – muscular
The brachial artery is larger than the radial artery. Meaning the brachial artery is more elastic than the radial artery. The smaller arteries will have a higher resistance i.e pressure, within them than the larger blood vessels because they are more muscular.
This differential pressure is necessary for the continuous flow of blood within the arterial tree. That’s the concept of the physics of flow through vessels of different sizes.
But of course nature is very clever, you have a sudden drop in pressure when blood arrives at the very small arteries called the arterioles. This is designed to protect us from harm and keep the delivery of nutrients and oxygen efficient.
I am digressing here for good reason but the video below explains it a little bit more about the physiology.
The point I am making is that; you will more than likely get higher blood pressure readings in the smaller radial artery (that the wrist monitors measures) than the larger brachial artery (that the upper arm monitor measures).
The second reason wrist monitors give inexact readings is that they are very sensitive to positioning. Any slight adjustment of your wrist position will lead to swings in blood pressure readings.
Which brings me nicely to the third reason for wrist blood pressure monitors inaccuracy. We advise high blood pressure patients to measure their blood pressure by placing the cuffed area to the level of the heart.
Now imagine trying to place the cuffed wrist at the level of the heart. It’s not a natural position for the wrist. That causes all sorts of positional problems.
Compared to the upper arm, which is almost at the level of the heart requiring just a little elevation, the wrist monitor will need a higher elevation. That’s a recipe for errors in blood pressure readings.
Would I recommend Wrist blood pressure monitors?
The short answer to that question is: No, I won’t.
They both recommend the upper arm monitors and I support the recommendation as well.
Why is this?
For the same reasons that I have outlined earlier on this article. It is clear. The wrist blood pressure monitor readings are not accurate. If you want to monitor your blood pressure at home, you’d want to use a device that is reliable.
You would use a blood pressure measurement device that produces clear, unambiguous blood pressure readings every time. Not some of the time but every time.
The wrist monitors cannot be trusted to do that. The wrist blood pressure monitors are not effective home BP monitoring kit.
The last thing you want is showing results of blood pressure readings to your doctor that are ambiguous and inaccurate. Situations like that will lead to your doctor making wrong management decisions.
You don’t want that. In fact, it could be downright dangerous. Avoid!
I shall be providing answers to these questions right here.
What are the pros and cons of wrist blood pressure monitors?
Sadly, I want to start with the cons of wrist blood pressure monitors. I apologize for this because it is never a good idea to begin a journey on a negative note.
Always start with the positives; my mother always told me when I was younger. But I am constrained to do disobey my mother in this instance, because I want to tell my story of my first romance with these wrist blood pressure monitors.
Wrist blood pressure monitor cons
And my story unfortunately does not lead to pros of wrist BP monitors but rather to the cons of wrist blood pressure monitors.
I am a sucker for innovation and innovative products. I needed to say this upfront as that’s how my relationship with these wrist blood pressure monitors started.
A couple of years ago, I saw a full-page newspaper ad on a brand of wrist blood pressure monitor. I was enthralled by the ad. Mainly because the focus of the ad was the simplicity of using this blood pressure machine. I was sold. In an instant.
I must admit at the time I had not heard of these wrist blood pressure monitors, so my curiousity was piqued. Really piqued. I went past curiousity and made a purchase straightaway.
I felt such an innovative product was something I needed in my life. I should say that I am a medical doctor and also someone who suffers from high blood pressure too. Therefore my need for the product was a match made in heaven.
In any case what’s the point of having your curiousity aroused by an innovative product and not do the follow through business – make the purchase, that is. Call it impulsive buying and you’ll be right.
I should also say that up until that point, I had not heard of wrist blood pressure monitors. They were not available in the hospital environment that I work at the time and still aren’t. I shall come to this point again later on…
Anyway, the product arrived a couple of days later and I was so keen to use it, I unboxed it straightaway.
Off I went, slammed it on my left wrist, pushed the button to inflate the cuff and measure my blood pressure. Oops…I got a ridiculously high reading. I sat back, rested a while, breathed deeply, tried another reading. Same high reading.
Tried wrist number 2 – same high reading.
Called the retailer who requested I send it back for exhange as that may be a faulty item. New wrist blood pressure monitor arrived days later. Same outcome.
Now, how do I know the wrist blood pressure monitor was the issue and not my blood pressure hitting the roof at 240/135 mmHg for instance? Well, that’s because I have an older upper arm monitor that I had been using reliably in the house.
I double-checked with that upper arm monitor and my blood pressure was perefctly normal at the same time the wrist blood pressure monitor was giving me ridiculously high blood pressure readings.
As stated in the video below, I tried some other brands of the wrist blood pressure monitors and I wasn’t impressed.
As you can tell from the above story, reliability and accuracy are big cons of the wrist blood pressure monitors.
The problem with accuracy and reliability are one big disadvantage of wrist blood pressure monitors that I find difficult to overlook.
One of the reasons wrist blood pressure monitors give higher readings that are not reflective ofyour true blood pressure is the artery who’s pressure is being measured.
Wrist blood pressure monitors take the blood pressure readings from the Radial artery unlike the upper arm monitors that measure the pressure in the Brachial artery.
The radial artery is narrower and more superficial compared to the brachial artery that is deeper and larger. If you remember your physics from secondary school, you will understand why the pressure in a smaller vessel will be higher than a bigger vessel.
Another problem with wrist blood pressure monitors is the placement of the blood pressure cuff. Ideally when measuring your blood pressure at home, we advise you to place the cuffed area at the level of the heart when the blood pressure measurement is taking place. This is actually the same advice offered by the American College of Cardiology too.
With the wrist monitors, the wrist where the cuff will be wrapped is not naturally at the level of the heart. Achieving that objective of having the cuffed wrist at the level of the heart makes for some awkward positioning.
This is very much unlike the upper arm monitors where the upper arm is almost at the level of the heart. Your arm only requires a little elevation.
Summary of the cons of wrist blood pressure monitors:
Difficulty positioning the cuffed wrist at the level of the heart
Readings very sensitive to positioning
Smaller blood vessel pressure being measured
Gives inaccurate readings most of the time
Reliable readings are few and far between
Therefore cannot be trusted as a home blood pressure monitoring kit
Pros of wrist blood pressure monitors
That said, it’s not all bad news with the wrist blood pressure monitors. They do have some advantages. May be it wasn’t a bad idea after all, that I started with the cons whilst tackling this subject of the wrist blood pressure pros and cons.
Saving the good news for last…
Anyway in the interest of a good balance of facts and without bias, here are the advantages of the wrist blood pressure monitors:
Wrist blood pressure monitors are small, therefore very easy to carry around. You can easily shove them in your handbag, briefcase and off you go. So, quite suitable for On-The-Go ambulatory blood pressure measurement.
Meaning they are very portable because they are small and lightweight.
They require very little dexterity to use them. You hardly need any handiwork to use the wrist blood pressure monitors. If you can wear a wrist watch, you can use the wrist blood pressure monitors.
Cuff size is usually not a problem with wrist blood pressure monitors. Because wrist sizes do not vary much, so you shouldn’t have an issue with cuff being too small or too big. Therefore suitable for those with big arms, although you can shop for bigger cuff for upper arm monitors too.
Practically all wrist blood pressure monitors are automatic as opposed to having to choose between manual and automatic. Meaning there’s very little learning curve involved.
This also translates to being very easy to use.
Summary of pros of wrist blood pressure monitors:
Small in size
Easy to use
Provides dual readings of systolic and distolic Blood pressure
Cuff size not usually a problem
Quite comfortable to wear and use
Little or no dexterity involved to get a blood pressure reading
Usually automated so little learning required
Wrist blood pressure monitors Vs Upper Arm Monitors: Which should I buy?
Those are the wrist blood pressure monitor pros and cons. Now, if you ask me which of these monitors to buy for your home use, my professional advice will be to go for the upper arm blood pressure monitors. Sounds crazy, right? After everything I’ve said…
See video below
As far as I am concerned, even though the wrist blood ressure monitors do have some really good advantages over the upper arm monitors, the one disadvantage I cannot get over is unreliability.
If you are going to monitor your blood pressure at home, you want something reliable. You want a blood pressure kit that gives you accurate readings that you can take to your doctor. Readings your doctor can trust.
Doctors don’t want to make decisions on blood pressure readings that are sketchy and probably accurate 25% of the time. Not even 75% of the time. We want to make decisions on readings that are accurate 99.99% of the time.
Why is this?
Doctors don’t want to make the wrong management decisions. Wrong readings lead to wrong decisions. That’s not the basis for a sound high blood pressure (hypertension) management.
Like I said in the video, given the fact that these wrist BP monitors have been around for a long time now, and are very easy to use, how come we don’t use them in hospital settings?
Let’s talk about nitrates in vegetables versus meat. Are the nitrates in vegetables Vs meat bad for you? Or are these nitrates good for you?
Is there a difference to how our bodies treat and interact with the nitrates in vegetables Vs nitrates in meat? Which of these nitrates is safer to eat? is it better to eat vegetables because of the nitrates and should we avoid meat because of the nitrates in meat?
I will endeavour to answer all of these questions in this article.
There has always been this debate about nitrates in food. We are all too concerned about our health these days and for good reason too. I’d like to know if what I am eating, especially on a regular basis, is good for my health or unwittingly damaging my health.
Time for “travelling in the dark” is far gone. The first thing to note is that there are nitrates in both plants and animal food produce.
I should say this upfront. I eat a plant-based diet.
But that is not to say, I don’t eat meat. I eat meat, fish and plants but I limit how much meat I eat. So, this article is not written with a vegetarian bias or anything like that because I am a full-blown flexitarian.
What’s the deal with these Nitrates and Nitrites in our food?
Nitrates are naturally occurring in plant food produce but in animal foods, they are artificially added to preserve these foods.
Nitrates are relatively harmless on their own. It is when they get converted to their subunits that the potential to cause harm arises.
Nitrates have 3 oxygen molecules attached to the Nitrogen atom.
However, nitrates become bioactive when one of the oxygen atoms is removed leaving 2 oxygen atoms attached to the Nitrogen atom. A Nitrogen atom with 2 oxygen molecules instead of 3 becomes a Nitrite.
So, the bioactive form of Nitrate is the Nitrite.
This conversion from Nitrate to Nitrite is trigerred by bacteria, fermentation, acid in the gut and ensuing enzymatic activity.
Why Nitrates are good for you?
This breakdown of Nitrate does not stop at the Nitrite step.
If you have ever pondered the question: are nitrates in vegetables bad for you? Well, you are going to love this analysis below because; it explains why nitrates in vegetables are not bad for you. It will encourage you to eat more vegetables, if anything.
Here it is: The Nitrite from the nitrate is further broken down to 2 other potential compounds – Nitric Oxide and Nitrosamines (N-Nitroso compounds also called NOCs).
The first piece of good news is; nitrates in vegetables tend to get converted to Nitric oxide more by default. Nitrates in meat on the other hand, have more potential to get converted to N-nitroso compounds for reasons I will explain later on.
You should celebrate Nitric Oxide because you want and need it. Plenty of it. Nitric Oxide optimizes our health in leaps and bounds.
Nitric oxide is beneficial to our health immensely. What’s weird is that, nitric oxide is actually a free radical but a nice free radical.
Usually free radicals are a ‘nasty piece of work’ as far as health is concerned, but Nitric oxide is one free radical that you don’t want to get rid of. You want it. Why?
…because Nitric oxide is a biological signalling molecule that enhances the function of the lining of our blood vessel walls. Not only that, Nitric oxide also protects the organelle in every cell of our body called the mitochondria.
Mitochondria is where energy production takes place. Every cell needs to make its own energy to function. That production factory is called mitochondria.
As it happens, Nitric oxide made from nitrates protects these tiny mitochondria organelles. This guarantees continuous efficient energy production.
The job of the Nitric oxide is to make the blood vessels walls pliable and more compliant. This enhances unhindered blood flow inside our blood vessels. Meaning oxygen and nutrients are carried to our tissues much more readily.
This allows for optimal health because this function of Nitric oxide lowers your global blood pressure – a recipe for control of high blood pressure.
Now you know why we advice you to eat beets, spinach, kale, celery, collard greens to lower high blood pressure or maintain a normal blood pressure. Nitric oxide supplied from the nitrates in these vegetables is the reason why.
Talking about optimal health, nitric oxide from nitrates in vegetables also prevents the stickiness of blood because it prevents what we call platelet aggregation. This activity thins your blood and helps prevents strokes and blood clots.
Why nitrates may be bad for you?
Nitrates can be a double-edged sword. They can swing either way.
As I said earlier, nitrates when broken down to nitrites could either become nitric oxide which we love and covet or become N-nitroso componds (NOCs) which you don’t want to touch with a barge pole.
These Nitrosamines (N-Nitroso compounds also called NOCs) are not really health-friendly. If you ever wondered about nitrates in food side effects, it is these N-nitroso compounds that are to blame. And I will talk about these nitrates in food side effects shortly.
Nitrosamines are bad news for your health.
The good news is that the nitrates in vegetables don’t appear to form the dreaded N-nitroso compounds. It is the nitrates from meat that tend to form these nasty N-nitroso compounds (NOCs).
Straightaway that’s the essential difference between nitrates in vegetables vs nitrates in meat. I shall explain later why the nitrates in vegetables behave differently to the nitrates in meat.
There’s plenty of evidence to support the notion that nitrates in meat are harmful.
Here is one. This analysis done by the World Cancer Research Fund found that eating just 1.8 ounces of processed meat per day — about one sausage or two to three slices of bacon — raised your likelihood of bowel cancer by 20%.
Are environmental Nitrates harmful?
From the epidemiological standpoint, nitrates are seen as harmful to human health. That is the reason there are regulations as to how much nitrate can be allowed in our drinking water. The amount of nitrate allowed in drinking water should not exceed 50 mg/l.
Because there is a risk of blue baby syndrome or what in medical parlance is called Methemoglobinemia. Young babies especially under 6 months of age are not able to deal with a large nitrate load. That environmental nitrate regulation is therefore essential.
The amount of nitrates in the soil is also subject to regulation. Why is this?
Excess nitrate in the soil will lead to a huge concentration of nitrates in our fruits and vegetables. We want some nitrates in our vegetables but we do not want excess nitrates in these plant produce.
More evidence to support the difference in Nitrates in Vegetables Vs Meat?
Well, the truth of the matter is research seems to tell us that there is a difference between nitrates in vegetables Vs meat.
The most studied vegetable is beetroot. There’s plenty of research evidence to support the beneficial effects of beetroot. This study even went further to look at the dose-dependent response of athletes to beetroot juice. It looked at cardiovascular health enhancement of beetroot juice and exercise performance.
The evidence seems to support the view that nitrates from vegetables like beet, celery, spinach, kale etc are safe and actually good for you.
Gunter Kuhnle, a professor of food and nutritional sciences at the University of Reading in the UK says:
“The nitrates in vegetables may be beneficial. When you eat nitrates, they are converted to nitrites by bacteria in your mouth”
Nitrates from animal sources however are not really naturally occurring. Nitrates in meat are added as preservatives.
The most commonly used nitrate in animal products is Sodium Nitrate. This and other nitrites are added to the meat to stop the growth of deadly bacteria. That way, you can eat your meat safely without the risk of food poisoning.
The nitrates and nitrites in meat also enhance the flavour of the processed meat whilst conferring on it a red or pinkish flavour. What kind of meat are we talking about?
We are talking about hot dogs, bacon, chorizo, pepperoni, ham, bacon, sausages, pastrami and salami. These processed meats contain artificial nitrates or nitrites in them. The nitrates in these processed meat are thought to be harmful to health.
This study examined the association of red meat, processed meat, and poultry consumption with the risk of early death in the European Prospective Investigation into Cancer and Nutrition (EPIC).
The study conclusion:
“The results of our analysis support a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer”
Why are the nitrates in vegetables like beet, celery, kale, spinach, arugula not harmful and the nitrates in meat harmful?
This question is not a very straightforward one but I shall do my best to clear the muddy waters.
For a start, it doesn’t matter the source of the nitrates. Whether you get your nitrates from vegetables or from meat, the increase in the amount of nitrates or nitrites absorbed into the circulation is essentially the same.
So, something else must be going on for this differential outcome between plant nitrates and meat nitrates.
Here’s what’s going on:
About 12 g of proteinacous material is offloaded into the large intestine every day. 50% of that is from dietary sources. This amount might vary a little bit depending on how much dietary protein is consumed and the physical form of the food consumed.
A careful breakdown of all of this consumed protein load takes place by bacterial action leading to deamination, decarboxylation and fermentation.
This process is dynamic, hence a higher concentration of amine byproducts are found in the tail end of the gut – the colorectal region compared to the earlier aspects of the intestines.
These amine substances react with nitrosating compounds leading to formation of N-nitroso compounds(NOCs) which are basically nitrosamines. These nitrosamines are not nice.
Nitrosamines (N-nitroso compounds) have been implicated in mutations and hence carcinogenicity.
This explains why the damage by these toxic substances is a lot more serious. For instance, cancers in the colorectal region. Mainly because the large intestines is a very fertile site for nitrosation and formation of nitrosamines, phenols and cresols.
But why does the nitrate in meat cause harm to health and nitrate in vegetables not lead to harm?
A scholarly explanation for nitrates in meat causing cancer has to do with the presence of heme-iron in meat as opposed to presence of non-heme iron in vegetables like celery, spinach, beet, kale, arugula.
Here’s what I mean.
We’ve already agreed that bacterial action in the large intestine acting on nitrates and nitrites leads to formation of toxic compounds like nitrosamines, phenols, cresols etc through fermentation.
Obviously this fermentation foisted by bacterial action applies to both meat and vegetable foods, right?
But the essential difference is the heme factor.
It would appear that the heme in the meat products up-regulates the formation of these potentially carcinogenic substances. You end up with more of these toxic mutagenic substances that are harmful to health when you consume meat.
Plus meat has saturated fat which may play a contributory role too.
Here’s what Professor Kuhnle had to say on the subject:
“What makes processed meats so ideal for forming N-nitroso compounds is that they have a combination of nitrite and proteins from the meat. And the meat’s heme seems to help convert them into N-nitroso compounds”
In contrast, plant foods like beet, celery, spinach, kale, collard greens (even though have nitrates) have non-heme iron and no saturated fats, so you have lower levels of these potentially harmful substances being formed. The levels do not reach a threshold that could induce colorectal cancer.
In addition to that; plants have hundreds of micro-nutrients that meats do not possess and these extra micronutrients in vegetables may offer our bodies a protective effect against cancer.
For instance, vegetables have Vitamin C and polyphenols that make it a harder task for nitrosamines to form. Meat hasn’t got Vitamin C nor does meat have polyphenols. This point should not be underestimated.
Hence, in the nitrates in vegetables vs meat debate, vegetables nitrates are safer for the human body to deal with. Meat nitrates on the other hand are potentially carcinogenic.
What can you do to make your meat safer?
See video below. You can make your bacon safer by using that preparation technique in the video below for your bacon.
Frying your bacon, baking it, broiling it or cooking in a baconer produces the most nitrosamines. The method in that video according to research produced the least amount of nitrosamines, hence it is recommended.
You may also use nitrate-free bacon, nitrate-free sausages, nitrate-free ham, nitrate-free hot dog. Use any of those, if you are someone who cannot do without processed meat in your diet.
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