Vegans, IGF-1, Vitamin B12, Homocysteine, and Stroke

There’s one area I think vegans need to be more knowledgable about, and that’s the issue of hemorrhagic strokes and their relation to our more likely lower levels of Insulin-like Growth Factor 1 (IGF-1) and vitamin B12. So I’ll do my utmost to clear all this up as simply as possible.

First, bottom line: As a vegan you should consciously limit your salt (sodium) intake, get regular exercise, eat a good high-fiber, moderate-good-fat diet, be sure to use a reliable source of B12 regularly, include organic non-gmo soy in your diet unless you cannot for some reason, and eat lots of folate-rich foods. (See “So here’s what to do…” numbered 1–6 below for details.) All of which you probably already do, except perhaps for the low-sodium part, which is important.

Now, what is IGF-1?

IGF-1 is a hormone similar in molecular structure to insulin; it’s a small polypeptide that is produced primarily in the liver in response to signals originating from the pituitary gland, naturally occurring in much larger amounts in children. But there is no need to include animal products in children’s diets to grow them faster…just be sure they’re well-nourished and active and they will produce the IGF-1 they need, especially if you include a bit of healthy soy in their diets (more on that below). No discernible impact of vegan or vegetarian diets on the growth of children has been found.

IGF-1 plays an important role in childhood growth and continues to have anabolic (muscle & strength improvement) effects in adults. It is necessary for proper growth in children, but studies of men and women more than 40 years old raise the possibility that it contributes to the growth of tumors in adults.(ref. 1) So it’s a good idea to keep our IGF-1 levels down, yet that in turn possibly increases our risk for hemorrhagic stroke because IGF-I acts on vascular tissue to promote vascular health. Yikes!…but wait…The dreaded and loathed SOY comes to the rescue.(ref. 2)  Also see “3. Soy” below.

Further, muscle growth is not dependent solely on the amount of IGF-1 circulating in the blood; muscle tissue produces its own IGF-1 in response to strength training to fuel muscle growth.(ref. 3) So a combination of regular strenuous exercise and a good vegan diet will result in lower levels of IGF-1 levels circulating in the blood (which is cancer preventive), while still allowing for local production of IGF-1 for muscle-building. But now, back to the strokes…

There are two kinds of strokes, ischemic and hemorrhagic.

Ischemic Strokes:Stroke_ischemic

This is where atherosclerosis (fat-clogged arteries) causes a clot to break off and block an artery to the brain. The brain cells that depend on this artery for blood then die. The ischemic type are the overwhelming majority of strokes (about 85%), and long-time vegans who eat properly are strongly protected against that type because vegans mostly have clear, pliable arteries, but that arterial flexibility common in vegans can also be a problem, more on that later.

Hemorrhagic Strokes:


These are less frequent and result from bleeding in the brain. This is the sort that vegans need to be more wary of, due to our more pliant arteries. This is where there is an arterial tear or rip, a break in a vein or capillary, or an aneurism breaking. (Aneurisms are “balloons” in arteries caused by weakening of arterial walls, usually due to genetics or high blood pressure.) Tears and breaks can occur in arteries that are softer and thereby weaker, which is said to be more common among vegans.

Flexible arteries, a problem?!

Not really; the benefits of flexible, clear arteries outweigh any problem. Factors that increase likelihood of arterial breaks for vegans are: 1) high blood pressure due to too much stress, too much dietary sodium, being overweight, and 2) low B12 levels and resulting high homocysteine levels which are thought to promote atherosclerosis (fatty deposits in blood vessels) by damaging the inner lining of arteries and promoting blood clots.(ref. 4)

Homocysteine is an amino acid (one of the building blocks that make up proteins) in our blood. Too much of it is a warning sign for coronary heart disease (CHD), stroke, and fatty deposits in arteries. High homocysteine is acquired mostly from eating meat, but also as a result of low B12! (Going by that surprising and ironic bit of info, it seems best for people to cut out the meat and take B12 supplement.)

Blausen_0259_CoronaryArteryDisease_02B12, folate(B9) and B6 are most effective at breaking down homocysteine in the blood; several studies showed higher levels of B vitamins are related to lower concentrations of homocysteine. Other evidence shows that low blood levels of folate are linked with a higher risk of fatal CHD and stroke. See “6. Folate” below. I thank goodness more than ever to have been enjoying a bit of nutritional yeast daily (loaded with B vitamins) since the mid-1980s when I first went vegan!

It’s interesting to note that while vegans were found to have at least a 25% lower risk of ischemic heart disease in several different studies, there was no difference between vegetarians, vegans and omnivores for stroke. Meaning vegans’ risk for stroke is about the same as everyone else’s, while we would expect our results to be better.

Pliable, clean arteries are actually a great thing because they significantly decrease our risk of ischemic stroke; but it’s a dilemma due to the possible risk for hemorrhagic stroke, so we need to know what to do to strike a healthy balance. Since on the other hand, low IGF-1 is a great thing for reducing cancer risk. Interestingly, animal protein is the main culprit in causing high levels of IGF-1 that contribute to tumor growth, as vegetable proteins such as beans don’t seem to have those same effects.(ref. 5)

Hemorrhagic stroke is far less common but more deadly than ischemic stroke. It’s why keeping blood pressure under control is especially important for those with more pliant arteries. [Hey, take up cigarette smoking to harden up those arteries! Haha, kidding, I amuse myself.]

So here’s what to do to solve this vegan dilemma, in my estimation:


  1. Sodium: Keep your blood pressure normal and low (120/80 or less), notably by keeping your salt (sodium) intake under control, no more than 2300 mg per day (preferably under 2000) if you’re under 51 and no more than 1500 mg for older, or those with known sodium sensitivity. (A teaspoon of salt has 2325 mg of sodium). Notably: Avoid processed foods with high sodium content. Also, high potassium foods like those awesome bananas counteract negative effects of sodium. See here for low-sodium guidelines:
  2. Diet: To help keep our weight down and benefit heart health, eat whole, high fiber foods often(ref. 6), including leafy greens, and keep fat intake sensible, say, less than 35% of total calories and concentrating on good fats like nuts, avocados, etc.
  3. Soy: Since a moderate level of IGF-1 is healthiest, and vegans tend to be on the low side, it’s best to include soy foods in your diet, as soy is known to up our levels of IGF-1 but not enough to raise risk for hormone-dependent cancers.(ref. 7) Unless you’re sensitive or allergic, eat organic non-gmo soy products like tofu, tempeh, and soy milk regularly. This increase in IGF-1 from soy serves to strengthen our arterial walls, as well as promote healthy growth in children. And note that soy may increase your need for iodine so, especially when restricting iodized salt, it’s wise to take a kelp tablet (225 mcg) on those days you’ve gone heavy on the soy (more than 2–3 servings).
  4. healthy familyExercise: Regularly, for your overall health and strength, including your cardiovascular health, which only makes sense and is commonly known, but sometimes we forget the importance of it. Walking, hiking, yoga, house cleaning, strenuous chores, strength training, etc. …all good.
  5. Vitamin B12: Do not downplay the importance of vitamin B12, and also realize that up to 40% of non-vegans are also deficient in this important vitamin due to absorbency issues and/or the ill health of the animals they eat (said animals often being supplemented with B12 along with other things including antibiotics). Symptoms of B12 deficiency in humans are: Sore tongue, weakness, weight loss, body odor, back pains, tingling arms & legs, insomnia, and pernicious anemia (symptoms: fatigue, tendency to bleed; pale, yellow skin; abdominal pain, stiff arms & legs, irritability, and depression). Any doubts about your B12 status, get a uMMA test, which is the most reliable, and if you’re 300 to 900 pg/ml (picograms per millileter), you’re absolutely fine. 500 mcg of B12 supplement every other day, or equivalent, should keep your B12 level quite healthy.
  6. vegetables-557891_640Folate: This is important for arterial health. Very fortunately, many foods high in folate (vitamin B9) are vegan, and most vegans eat plenty of these; if you don’t, it’s wise to start, and eat raw often. Those foods include: Nutritional yeast, spinach (and all greens like broccoli & lettuce), black-eyed peas, beans, lentils, asparagus, brussels sprouts, sunflower seeds, flax seeds, avocado, green peas, kidney beans, peanuts, wheat germ, tomato juice, oranges, turnip greens, papaya, banana, cantaloupe. Note that most folate-rich foods are also rich in B6, and ground flax seeds also supply us with essential fatty acids (omega-3)…showing just how awesome foods from the Earth are. NOTE: Folic acid supplement (synthetic form of folate) is strongly advised against by many nutrition professionals, who say we only get proper folate from foods, and that we should only take a minimum of nutritional supplements that we cannot (or do not) get naturally.

Much ado about nothing?

Fortunately for vegans, all this isn’t as scary or complicated as it seems, since things seem to balance out, where one thing may cause a problem, some other aspect may correct that problem, since our vegan lifestyles usually are inherently quite healthy. So most of us are likely to realize we’re already doing those beneficial countermeasures, without trying. My only changes upon learning all of this were to cut out some of the salt and be more determined to lose a few pounds. But it’s good to be as informed as possible on all of this, and to understand it somewhat, since we’re needed in this world, as a force for great and much-needed changes. We need to be (and stay) healthy, live long, and be mentally aware and sharp. And our diet and lifestyle overall, when done right, are great for all of that. And most importantly of all, we want to free all of those dear lives from those prisons and slaughterhouses:


I hope this was helpful and not too long or confusing. Thanks for reading 🙂




This article provides information that should not take the place of professional advice. I am not a nutrition or health professional but am sharing what I’ve learned through experience and from what I trust are good sources in regard to my own nutrition. If you have concerns, I encourage you to talk to a (vegan friendly) registered dietitian or other trusted professional about your dietary needs.

(Images are all labeled free to reuse.)


2 thoughts on “Vegans, IGF-1, Vitamin B12, Homocysteine, and Stroke

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