Nutrition for High Blood Pressure

“You should lose weight and lower your salt intake.” That’s about the extent of the advice that people get when trying to lower their blood pressure.

While it may be sensible advice, there are a number of other, easy things you can do to lower your blood pressure.

That’s what you’ll learn about in this module:

  • The 5 reasons someone might have high blood pressure
  • Which foods to eat more of to help you lower your blood pressure The caffeine controversy
  • Which foods to eat less of

The coolest part is you don’t need to lose weight to lower your blood pressure. That’s not to say that you shouldn’t. If you’re overweight, losing weight will certainly make you healthier, but it’s not a requirement for improving your blood pressure.

5 Reasons for High Blood Pressure

There is more than one reason why blood pressure might be high:

Stress

If you’ve been reading about health, you must have come across a hormone called “cortisol.” The media has dubbed it “the stress hormone.” For good reason. Because your body releases more of it when you’re under stress.

See, you release cortisol all the time anyway, whether you’re stressed, or relaxed. You just release more of it under stress.

Since our bodies have not caught up to the modern world, they’re stuck in a world that’s about 40,000 years old. Forty thousand years ago, about the only 2 things that stressed us out were famines and sabre-toothed tigers.

Just think about it, if you’re running away from a sabre-toothed tiger, you’d want:

  • Your blood sugar to rise, to give fuel to working muscles
  • Your blood pressure to rise, to push the blood to your legs faster
  • Your digestion to stop working, so that it doesn’t use up energy that

should be getting used up by the muscles

  • Your reproductive system to stop working, also to not use up energy that should be getting used up by the muscles

From an evolutionary perspective, high blood pressure was very beneficial, because it was just temporary, until the stressor went away. But in our modern world, we’re not stressed because we’re running away from a sabre-toothed tiger. Instead, we’re stressed because of relationships, finances, deadlines, etc. However, to our body, it doesn’t matter. Whether stress is physical (exercise or famine), or mental/emotional, the hormonal response is the same: high cortisol.

In the pharmaceutical world, the way they deal with it is by blocking adrenaline (which is basically turbo-charged cortisol) either at the level of the heart (the term for that is “beta blockers”), or at the level of the brain (the term for that is “central alpha agonists”).

Are there foods that do this naturally? Yep. Celery (2-3 medium stalks) and garlic (2-3 cloves). In fact, one thorough meta-analysis18 showed that garlic can lower blood pressure by as much as 8.4/7.2 mmHg.

Narrow Arteries

Arteries take blood away from the heart. They’re a tube. But if that tube gets narrower, the blood will push out against the walls harder. After all, the volume of blood in your body doesn’t change. But if there’s less space for that blood, it will push out against the arteries harder.

What causes the arteries to narrow? A hormone called “angiotensin.” That’s why in the pharmaceutical world, there’s a class of drugs called “ACE inhibitors”, which stands for angiotensin-converting-enzyme inhibitors. Without getting too deep into the mechanism of action, the end result is lower angiotensin levels, and therefore, wider blood vessels.

Fortunately, natural compounds found in normal foods can also inhibit this enzyme, and widen blood vessels. What are some examples of foods that open up blood vessels by decreasing angiotensin?

  • Dairy products (especially cheddar cheese, gouda, yogurt and sour milk)
  • Egg yolks
  • Tuna
  • Beef
  • Sardines
  • Garlic
  • Spinach
  • Grapes
  • Broccoli
  • Buckwheat
  • Rice

Think it makes sense to eat these if you want to lower blood pressure? You bet!

By the way, this list is by no means exhaustive. There was one very comprehensive study done on the subject, so for the geeks who want to delve deeper into it, check it out here; ( https://onlinelibrary.wiley.com/doi/full/10.1111/1541-4337.12051)

Another way to make arteries open wider is not to affect angiotensin, but to prevent the muscles surrounding your arteries from contracting. The mineral needed for arteries to contract is calcium. So we want to prevent calcium from binding to its receptors on muscle cells, which causes them to contract. In pharmaceutical terms, these are called “calcium channel blockers.”

If you’re wondering “are there foods that can naturally act as calcium channel blockers?” The answer is yes! Celery (again, 2-3 medium stalks) and garlic (2-3 cloves) act as natural calcium channel blockers, according to a study on hypertension, drugs, nutrition and nutraceuticals. If you’re wondering “should I avoid calcium supplements?”, unfortunately I have to refer you to your pharmacist on that one, since there are a number of different considerations.

Excess Fluid/High Sodium

Another potential reason why blood pressure might be high is due to excess fluid inside the arteries. You might be wondering “how does excess fluid end up in the arteries in the first place?” Good question. When you eat more sodium than you should, your body holds on to it. Sodium attracts water, so you don’t just get sodium, you get more water in the arteries than you should have.

That’s why there’s a class of drugs known as “diuretics” that help the body get rid of excess sodium, and along with it, excess water. Less water in the arteries, less force against the arteries.

Are there foods with natural diuretic properties? You bet! Parsley (minimum half a cup), asparagus (minimum half a cup, or 6 medium spears), watermelon (1 cup), and celery (2-3 stalks) all fit the bill (hmm… did we just see celery in 3 different categories? I think we did!).

Low Potassium

The mineral that counterbalances sodium is potassium. When you eat the right amount of potassium (which is around 4700 mg/day), it keeps sodium in balance, which in turn prevents excess water from accumulating inside the arteries. Additionally, potassium opens up blood vessels in its own right.

In fact, one study found that the higher the dietary potassium intake, the lower the blood pressure, and the greatest effects of dietary potassium happen in those with higher blood pressure.

In another study, comparing the effects of dietary potassium in take and the need for antihypertensive medication, a group of people was told to increase potassium in their diet (and the researchers measured that indeed, they were consuming more potassium by checking their urine for potassium), and found that 81% of people who increased their potassium intake lowered their medications by 50%. The real cool part is that these changes happened without any loss in weight.

Which foods are high in potassium?

  • Dates (5 dates are about 835 mg of potassium)
  • Prunes (10 prunes are nearly 700 mg)
  • Potatoes (one large potato has about 1600 mg)
  • Bananas (1 medium banana has about 422 mg)
  • Avocados (half an avocado has nearly 500 mg)
  • Sun-dried tomatoes (20 sun-dried tomatoes have about 1400 mg) 
  • Sweet potatoes (1 cup of sweet potatoes has about 950 mg)

Low Magnesium

Another possible reason why the arteries may be too narrow is a diet low in magnesium. This important mineral is responsible for relaxation. It relaxes the muscles, the heart, the bowels (know what I’m saying? ), and it also relaxes the smooth muscles surrounding the arteries. In fact, cardiologists in a 2015 article23 showed a 7.0/3.8 mmHg difference in blood pressure between people eating magnesium-rich diets and magnesium-poor diets.

Think it makes sense to raise your magnesium intake if you have high blood pressure? You bet it does.

The foods with the highest magnesium content are Brazil nuts (get at least 6 nuts), almonds (get at least 20-25 almonds), and dark chocolate (the darker, the more magnesium it contains. The minimum is 70% cocoa. Go for 30- 60 grams, or 1-2 ounces).

As you can see, the vast majority of reasons behind high blood pressure are just about opening up blood vessels. There are multiple ways of doing that.

There is a natural chemical produced in all of our bodies, called “nitric oxide.” Another natural chemical in foods, called “nitrates” helps the body produce its own nitric oxide. What are foods high in nitrates?

  • Beets (a cup a day)
  • Spinach (a cup a day)
  • Celery (6 stalks per day) 
  • Lettuce (a cup a day)

In a study on hypertension24, when people consumed a nitrate-rich drink for 4 weeks, their blood pressure was reduced by 7.7/5.2 mmHg. The nitrate-rich drink was standardized to about 250 mg of nitrate. This amount of nitrate is found in about 100 grams of beets, celery, and spinach.

Another common food that has been well-studied in its effects on high blood pressure is flax seeds. In one study, hypertensive people who ate just 30 grams of flax seeds per day lowered their blood pressure by 15/7 mmHg in 6 months.

When working with clients, I like to keep it simple. I give them this list of foods, and I ask them to just eat one of those with each meal. They have a quota. And now, you have one too

If you’ve read about nutrition for high blood pressure in the past, you must have come across the DASH diet (Dietary Approaches to Stop Hypertension), so if the above looks like the DASH diet to you, it’s similar.

The Caffeine Controversy

And now, for one of the least popular sections of this program: caffeine restriction. I know, you love your morning cuppa Joe, and you need a little boost in the afternoon, when your energy levels are down, but you keep hearing that caffeine increases your blood pressure. Should you cut it out? Or keep it? Let’s look at what the evidence has to say.

Several studies, have shown that caffeine does raise blood pressure. These studies find that the increase is fairly modest in general (only about 4/2 mmHg), but that’s in all people – those with high blood pressure, and those without. If you look only at people who already have pre-existing high blood pressure, they seem to be more responsive to the effects of caffeine compared to those without high blood pressure, according to a critical reviews27,28. So their blood pressure rises higher than those without high blood pressure.

Now yes, according to recent studies27, tolerance to caffeine does develop in some people (meaning that their blood pressure doesn’t rise as much after they’ve been a regular coffee drinker for a while), but not all people.

How does caffeine raise blood pressure? What’s the mechanism? Although it’s not 100% clear, the main theories are that it blocks a chemical called “adenosine.” Adenosine causes the relaxation of blood vessels. So if you block relaxation, you get the opposite – tension.

How long does the blood pressure-raising effect of caffeine last? On average, about 3 hours, but in some people, it’s much longer than that. And remember – those who already have high blood pressure are more sensitive to caffeine than those without high blood pressure.

Want to find out how long caffeine affects you, specifically? Here’s how you do that:

Step 1: measure your blood pressure.

Step 2: drink your coffee or tea. Drink it in the amounts and concentrations you normally drink.

Step 3: measure your blood pressure every hour, until it returns to normal.

If you want to add validity to this experiment, repeat it on 3-5 different days.

But really, the reason that we’re worried about high blood pressure in the first place is because of the risk for heart attacks and strokes. So why not measure whether caffeine actually has an impact on risk of heart attacks and strokes, as opposed to blood pressure? According to one systematic review , although caffeine does raise blood pressure for 3 hours, it does not raise the risk of heart attacks and strokes. Isn’t that great news? Want to go and celebrate with a coffee?

What do we make of all this information? If you don’t already have high blood pressure, drinking caffeine won’t give you high blood pressure. Enjoy. But if you already have pre-existing high blood pressure, drinking caffeine will raise your blood pressure for a few hours. If you’re drinking 2 or more cups a day, your blood pressure may be elevated for all of your waking hours. Also, keep in mind that most studies looking at the effects of caffeine use a dose of 250-300 mg/day. That’s about 2 cups of coffee. If you’re drinking more than that, there’s no great evidence to say if it’s still neutral, or starts to become harmful.

Overall, if you want to be super safe, and you think you can handle it, either stop drinking it, or stick to decaf. If you want to go with what the evidence says right now (remember, evidence changes all the time), you can have up to 2 cups of coffee per day relatively safely.

Now, what about tea? I mean, tea has caffeine as well, doesn’t it? Yes, it does, but paradoxically, although drinking tea raises blood pressure in the short term (by a lot, by the way. About 5/3 mmHg for green tea, and 10/5 mmHg for black tea), for up to 30 minutes (according to an article30 published on the “Effects On Blood Pressure Of Drinking Green And Black Tea”), it seems to return back to baseline by about an hour.

However, the real question is not so much the short-term effects of tea, but the long-term effects. The long-term effects of tea are quite favourable. One systematic review found that consumption of green tea lowers systolic blood pressure by a modest amount (about 2 mmHg). Black tea also lowers it by a similar amount, although also appears to have a small effect on diastolic blood pressure as well, according to data gathered.

But the real winner of all teas is hibiscus tea. In a 2009 study published, when people with pre-hypertension and mild hypertension drank 3 cups per day for 6 weeks, their blood pressure dropped by an average of 7/3 mmHg.

If you’re wondering “what about decaffeinated green of black tea?”, the answer is that we have no research investigating their effects on high blood pressure. But I will give my opinion. Tea doesn’t lower blood pressure because of its caffeine content. Rather, it lowers blood pressure in spite of it. Tea contains a natural chemical in it called “theanine”, which calms down the nervous system. That’s one mechanism that we are aware of. However, there are likely other natural chemicals in tea that in combination with each other, lower blood pressure.

Which Foods to Eat Less of

We all know that sodium/salt is a common recommendation for lowering blood pressure. Why? Because where sodium goes, water goes. If sodium goes into your arteries, water goes along with it, which increases the volume of fluid inside the arteries. That causes the fluid to push harder.

That’s why lowering sodium intake is a common recommendation. Most canned/boxed foods (outside of fruits and veggies) are high in sodium, but on the natural side of things, pickles (actually, anything pickled) and olives are high in sodium.

Not everyone with high blood pressure needs to restrict sodium. In some people, it doesn’t have much of an effect, whereas in others it has a very large effect. The way to figure it out is to try a low-sodium diet for 1 week (that’s 1500 mg of sodium per day or less), and see the differences in your blood pressure. If it dropped by at least 5-6 mmHg, it’s a good idea to stay on the low sodium diet.

But if it didn’t drop much, you’re probably fine to keep it in there.

Some of you may be wondering “are there differences between the different types of salt (Himalayan salt, sea salt, Celtic salt, etc.)?” Unfortunately there’s no research that I’m aware of investigating the effects of these different types of salt on blood pressure. So this is where I give my 2 cents. The ultimate determinant of the blood pressure-raising effect of salt is the sodium content.

One gram of regular table salt (about a fifth of a teaspoon) has about 387 mg of sodium. One gram of sea salt has about 468 mg of sodium. One gram of Himalayan (pink) salt has about 283 mg of sodium. So you’re thinking “ah-ha! I’ll just switch to Himalayan salt, because it has less sodium.” But keep in mind that because it has less sodium, you’ll just have to use more of it to get the same taste as table salt.

Very often, people are quick to point out that Himalayan salt has more potassium, magnesium and calcium than regular table salt, and it does. One gram of Himalayan salt has a whopping 4 mg of calcium (we need 1200-1500 mg/day), 0.2 mg of magnesium (we need 300-500 mg/day), and 3.5 mg of potassium (we need up to 4700 mg/day). So for all intents and purposes, the differences between the different kinds of salt is negligible… in my opinion.

But if you really want to be sure, you can do your own study on yourself.

For a week, keep track of how much salt you use (whatever type of salt you do use), and concurrently measure your blood pressure. The following week, use the same amount, but of a different type of salt, and keep measuring your blood pressure. If it dropped, you know that the new type of salt you used has more favourable effects on your blood pressure. If it didn’t drop, you know it didn’t work.

Alcohol

While with caffeine, I was able to at least give you some good news, with alcohol, I can’t do the same. The research is quite clear on alcohol. At best, it’s neutral (note: “neutral” does not mean “healthy.” Neutral just means it doesn’t make your health worse, but it doesn’t make it better). At worst, it raises blood pressure. And the “at best” scenario is only if you drink no more than 1-2 drinks per day if you’re a man, and 1 drink per day if you’re a woman.

Just so we’re all on the same page, how much is a “drink”? It’s 14 grams of pure alcohol. This amount is found in about 350 ml (12 oz.) of beer and 150 ml (5 oz.) of wine.

Any more than those numbers, and blood pressure starts to rise according to studies.

The primary theory on the reasons that alcohol raises blood pressure, according to the study on alcohol induced hypertension, are that it decreases nitric oxide – a chemical needed for the blood vessels to dilate. The second reason is that alcohol damages the inside of blood vessels, which also stiffens them, and makes them unable to dilate.

Food Sensitivities

While most of what I write about has substantial research behind it, food sensitivities don’t fit in that category. But I feel the need to write about it, since there is good mechanistic evidence.

First – what’s a food sensitivity? Is it the same as an allergy? Not quite. A sensitivity is like a low-grade allergy. The difference is that allergies are severe and immediate. For instance, you eat a peanut, and within seconds, your throat shuts. Or you eat shellfish, and within a few minutes, your skin breaks out in hives. Those are outright allergies. By contrast, sensitivities are subtle and delayed. For instance, you eat gluten (usually found in wheat, rye and barley), and next day, your joints are stiff. Or you drink dairy, and 2 days later, your nose is congested.

Because sensitivities are subtle and delayed, you may go your whole life, and not know you have it. And it’s not quite so easy to figure out, since it may be otherwise healthy foods, like spinach and chicken.

Why would food sensitivities raise blood pressure? If you’re eating something that you like, but doesn’t work so well for your body, it releases too much cortisol, which could narrow the arteries. The other mechanism is you could retain water from that food, so you have too much fluid inside your arteries.

So investigating what your own food sensitivities are is certainly worth a shot if you have high blood pressure. How would you figure that out?

In order to investigate food sensitivities in my clients, I prefer to use a test that measures IgG, IgA, IgM and IgE which is a laboratory test that accurately pinpoints food sensitivities. This test lists approximately 200 different foods. There are pros and cons to this method. The pros: speed (5-7 business days) and accuracy (although older IgG-only tests had a lot of inaccurate results, newer tests from advanced laboratories are much better). The cons: price. It ain’t cheap (typically between $450 and $1800 at the time of this writing).

If you prefer to not do the lab test, then you can go the route of doing an elimination diet. The downside of this option, although it may cost a lot less, is that you have to exercise self-discipline. To accurately find out what you are sensitive to, you have to eliminate the most common allergens for the four-week test period.

This means reading labels and being very careful about what you eat. That leaves you with plenty of vegetables (except for potatoes, tomatoes, bell peppers, egg plants, corn, and chili peppers), most meats (except pork), and most nuts and seeds, in addition to all fruit. You can eat any of these in unlimited quantities. You should not go hungry -this is important.

What do you eliminate? Start with the most common allergens in North America, which are gluten, dairy, sugar, corn, and soy. Also, if you want to make it specific to you, eliminate/replace the foods that you eat on a regular basis. Do you have chicken every day? Try replacing it with turkey for this 4- week period. Do you eat tomatoes daily? Try replacing those with an alternative as well. It’s often the foods you eat most often (even if they are otherwise healthy foods) that you are likely to be sensitive to.

After removing all of these foods for 4 weeks, on day 29, you bring back just 1 of them, and note your symptoms. Note things like joint pain, skin quality, bowel movements, nasal congestion, mood, and most importantly, measure your blood pressure. If all of those are unchanged when you bring back a food that you eliminated, you can keep it in. After 3 days, bring back another food that you eliminated. Continue to bring back 1 food every 3 days, until they’ve all returned.

Now, what do you do if you bring back an eliminated food, and you do see changes in symptoms? Remove it for another month, and bring it back in again. If it produces the same symptoms (and an elevation in blood pressure) the second time around, it’s probably a good idea to keep it out permanently.

Sometimes, something as simple as removing food that you might have been eating your whole life can normalize your blood pressure relatively quickly (even if it’s an otherwise healthy food).

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