Vegan Health and Fitness

When I went to the doctor for my annual physical after adopting a vegan diet, I was a little surprised that he wanted to check my iron levels to make sure I didn’t have anemia.

My iron levels were fine, but the truth behind dietary iron is surprising. While my doctor was concerned about anemia, it turns out that iron overload is now becoming more common in the United States than iron deficiency.

Non-heme iron better than heme iron

There are two types of iron: heme iron that is only found in meat and non-heme iron that is the only kind found in plants.

Heme iron is found in shellfish, red meat, poultry, and fish with the darkest meats containing the most iron. It is the most readily absorbed form of iron and you generally absorb between 15% to 35% of the heme iron you consume. However its uptake is unregulated – so consuming too much meat, especially red meat, can eventually lead to iron overload.

Non heme iron, is the only form of iron found in plants, but is also present in eggs, milk and meat. It is less easily absorbed with only 2% to 20% being absorbed. Unlike heme iron its uptake is regulated; your body will only use the iron it needs. So a vegan diet avoids the risk of iron overload.

Iron deficiency is no more common in vegans than in the normal population presumably because typical vegan foods contain high amounts of non-heme iron.

Too much iron is bad for you

Too much iron creates free radicals which in turn wreak havoc within your body. Elevated iron stores have been associated with many diseases including inflammation, arthritis, diabetes, gall stones, cancer and heart disease.

Your stores of iron accumulate with the absorption of dietary iron, but your body has no mechanism for excreting excess iron. Although regular loss of blood though blood donation or menstruation can offer some protection against iron overload.

Studies have shown an almost linear increase of iron stores with age in men eating a typical diet. Iron stores in vegans tend to be lower, lowering their risk of disease without making them any more prone to deficiency.

Another risk to consider is that one in every two hundred people have the genetic mutation for hereditary hemochromatosis – this often undiagnosed condition results in two to three times as much dietary iron being absorbed than normal.

Making the most of your iron

Foods such as beans and greens contain plenty of safe non-heme iron whereas supplements contain potentially dangerous heme iron. So to meet your iron needs I would recommend eating plenty of iron rich plant foods and avoiding supplements containing iron unless you are undergoing treatment for a diagnosed iron deficiency.

Some foods containing phytates (whole grains, legumes, nuts and seeds), polyphenols (coffee, tea, red wine) and calcium supplements can inhibit non-heme iron absorption. However vitamin C (plentiful in greens and fruit) can increase iron absorption by as much as 30%.

You need to replace 0.9 mg per day of iron lost through bodily processes . Menstruating females need to replace an additional 0.4 mg per day. Pregnancy or lactation requires an additional 4 mg per day.

Recommended Daily Intake

Given the range of absorption levels, the daily recommended intake may not be very accurate for you personally. The recommendations are 1.8 times higher for vegans and vegetarians. However, as is often the case with these kinds of recommendations, a worst case diet (biased towards inhibitors) was assumed.

Institute of Medicine Iron RDI (omnivore/vegetarian):

• Men and post-menopausal women (8mg/14.4mg)
• Menstruating Females (18mg/32.5mg)
• Breastfeeding (9mg/16.2mg)
• Pregnancy (27mg/48.6mg)

Generally if you are eating a healthy vegan diet you will be getting plenty of non-heme iron.

You can optimize your intake by:

• Eating lots of iron rich plant foods such as legumes and greens
• Avoiding tea, coffee and calcium supplements during meals
• Including vitamin C rich foods such as greens and fruit in your meals

If you are switching from a standard American diet to a plant-based diet you will almost certainly be adopting a more nutritionally complete diet. And while you might be inspired to do some fine tuning – you can generally rest easy knowing that your nutritional needs are being met.

Except, that is, for vitamin B12.

What is B12

B12 which is also known as cobalamin, is a water soluble vitamin essential for the normal functioning of the brain and nervous system, and for the formation of blood. It is the largest and most complicated vitamin and can only be produced by certain bacteria.

B12 from animal products

B12 is present in meat and milk because animals either consume food contaminated with B12 producing bacteria (they don’t worry about grabbing a mouth full of earth with their food) or they are ruminants (cows) that can get B12 from bacteria in their gut.

However even the levels of B12 in animal meat and milk can be a concern. B12 in milk is depleted by sterilization (pasteurization or ultra-heat treatment). Most farm animals are fed corn or grain grown on sterilized soil supplemented by inorganic NPK (nitrogen, phosphorus, potassium) fertilizers – soil that is likely devoid of the B12 producing bacteria. And modern factory farmed animals are pumped full of antibiotics which may inhibit the B12 producing bacteria in their guts.

Some recent studies have shown that B12 deficiencies are actually more prevalent or as prevalent in people on a standard American diet. With maybe two thirds of the population flirting with B12 deficiencies.

Also the ability to absorb sufficient B12 from animal products seems to be an issue especially as people age – with a recommendation that everyone over the age of 50 should take supplemental B12.

B12 From Plants

It has been suggested that B12 can be found in a number of plant food sources such as tempeh, nutritional yeast, spirulina and seaweed. However no reliable plant source of B12 has yet been found.

B12 has been found in batches of mushrooms, seaweeds and fermented foods, but the presence of B12 in these foods is not considered reliable enough for you to bet your health on it.

Spirulina and other algae are of special interest because they contain a pseudo-B12 and these inactive B12 analogues do not work as B12 in humans. In fact its presence can act as a false positive in the immunoassay test used for testing B12. So if you consume spirulina and get a standard B12 blood test – the test could falsely show high levels of B12, but you might actually be deficient in B12.

Nutritional Yeast only contains B12 when it has been artificially fortified with B12 and not all nutritional yeast is fortified so you need to check the nutrition label.

Natural Diet Advocates

Some evangelists really like the idea that a vegan diet is a naturally healthy diet that shouldn’t require supplementation.

However the consensus of the vegan community and the medical evidence show that B12 deficiency is a real risk for vegans who do not supplement.

There maybe cases of vegan’s thriving without B12 supplementation, however these are in the minority and we don’t know the specifics. Maybe they are highly efficient at processing B12, maybe they are consuming B12 supplemented foods without realizing it, maybe they are consuming food contaminated with B12 producing bacteria.

Up to 30 years of B12 can be stored in the body, so maybe some people are just living off their reserves and storing up trouble for the future.

It may be, as some suggest, that most healthy individuals don’t require B12 supplementation and all cases of B12 deficiency in humans are due to some other confounding factor.

However, supplementation with B12 is safe and easy and a B12 deficiency can result in permanent neurological damage, so it would seem that the sensible option would be supplementation.

B12 Supplements

B12 can be found in most supplements and many foods such as soy milk are fortified with B12.

The regular form of B12 (cobalamin) used in supplements is cyanocobalamin – which is an inactive form of B12 bound to cyanide. This is broken down by metabolism into methylcobalamin and cyanide. Cyanide is a poison but is assumed to be tolerable at these small doses except for people who exhibit cyanide sensitivities. Flushing the cyanide out of your system does use up some antioxidants so this form of B12 may be putting a slight additional strain on your body.

A number of quality supplements contain an active form of B12 methylcobalamin that does not need to be metabolized making it more bioavailable which could be an advantage for people with certain health issues. It also has the advantage of not exposing you to that small dose of cyanide.

The natural form of B12 is hydroxocobalamin and can be intravenously injected to treat diagnosed B12 vitamin deficiencies.

B12 can also be absorbed sublingually (under your tongue). This method bypasses the digestive system so it may be more suitable for people with serious digestive disorders.

My Conclusion

Based on my research I have chosen to take a supplement that contains the high quality form of B12 methylcobalamin. I expect any form of B12 supplimentation would be sufficient, but I have been able to find this potentially better form of B12 in a quality multivitamin which keeps my life simple.

I take Dr Fuhrman’s Gentle Care Formula Vegan Multivitamin, but there are hundreds of other methylcobalamine B12 products on Amazon.

There is a conflict over what we eat going on between the vegan advocates and the meat and dairy promoters. With the recent release of the film Forks Over Knives raising the ante.

Vegan advocates are excited to promote a vegan diet that:

• appears to be considerably healthier than the standard American diet
• doesn’t require us to exploit animals
• puts less of a burden on our environment

However are some going a little to far in their enthusiasm to spread the message to a larger audience?

Herbivore or Carnivore

Some vegan advocates have suggested that we are natural herbivores whilst meat eaters have argued that we are natural carnivores. These are false dichotomies – the truth is more complex.

Here are some arguments from the herbivores:

• Our intestines are designed for digesting plants not meat
• Meat eating is a recent development in human evolution that we haven’t adapted to
• Herbivores and plant eating primates like gorillas do fine just eating plants

And here are some counter arguments from the carnivores:

• Humans were made to eat animals
• Primitive man ate a diet primarily of meat
• Humans cannot survive without nutrients only found in meat

Let’s take a look at the facts behind these arguments.

Digestive Systems

Herbivores have long digestive systems optimized for breaking down cellulose whereas carnivores have short highly acidic digestives systems optimized for the quick processing and elimination of meat.

Our digestive system is indeed longer and considerably less acidic than those of carnivores, but it is also different than those of herbivores. Our digestive systems are shorter than those of herbivores, we do not ruminate like cows, we don’t regurgitate like rabbits and gorillas and we don’t have an extra large cecums like horses.

We have the intestines of an omnivore, a highly flexible digestive system that can deal with both plants and meat. However nothing in nature is black and white and in our case we don’t have the herbivores ability to break down foods with a high cellulose content and we don’t have the high acidity which allows carnivores to safely consume raw meat and carrion.

So we are biased towards more easily digestible plants, but we can consume higher cellulose foods and meat through cooking.

Human evolution

Archeological evidence shows that our ancestors have generally consumed some amount of animal products throughout our entire evolution. For most of that time meat consumption was probably very similar to our closest cousins the chimps at about 5% of calories.

About 35 thousand years ago Cro-Magnons managed to thrive in the cold climate of Europe through big game hunting. During this period and the coldest years of the Ice Age, meat consumption may have risen to as much as 50% of calories.

With the advent of agriculture in the Neolithic age meat consumption dropped back down to around 10% of calories.

And with the standard American diet we now consume about 69% of calories from animal sources.

The ability to eat plants when they were plentiful and eat meat during hard times has been a highly beneficial adaptation.

Herbivores, Primates and B12

Herbivores have specific adaptations which allow them to digest foods with a high cellulose content. They also have B12 rich bacteria in their gut which is absorbed through rumination and regurgitation. So whilst they clearly demonstrate that strong healthy animals can thrive on a 100% plant diet, they are not an ideal human comparison.

If we look at our closest cousins, the primates, we see that they have a number of mechanisms which allow them to get B12. Most monkeys including chimps eat meat. Those that do not eat meat have herbivore like digestive systems and also tend to consume B12 rich insects and bacteria along with the plants that they eat.

Gorilla’s, possibly the closest to vegan of the primates, regurgitate their food, eat insects and sometimes eat their own feces. Interestingly there have been some reports of wild animals kept in captivity and fed sterilized diets developing B12 deficiencies.

As for humans we are very efficient at utilizing and recycling B12 and we may even have as much as a 30 year reserve of B12. In the past bacterial contamination of our food with B12 rich strains of bacteria may have been sufficient to meet our B12 dietary needs even without animal sources.

The highly sterilized food sources of today may not provide us with a reliable source of B12. This last point is still somewhat controversial as most B12 deficiencies tend to present with confounding factors such as other dietary deficiencies or absorption problems. However most vegan coaches recommend some form of B12 supplementation just in case.

Shades of Grey

A lot of the arguments out there for or against a vegan diet tend to be black and white. As always the truth as always is more complex and what we need to focus on is the affect that modern food has on modern humans.

There is mounting evidence that the standard American diet with its high animal product and processed food content and low whole plant food content is harmful over the long run.

I choose a vegan diet, because it has been personally beneficial for me, it falls within the range of diets that are likely to be optimally healthy based on the current evidence available and because I find it easier and more enjoyable to eat a healthy vegan diet.

Are there other arguments for or against veganism that you have heard?

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When trying to understand your cholesterol numbers you will come across two distinct pieces of advice – lower your overall cholesterol and make sure your total cholesterol to HDL ratio is good. However you seldom see these two pieces of advice discussed together. So what should you do if your overall cholesterol level is high, but so is your HDL?

Focus on HDL and total cholesterol

The simple answer is you need to focus on both. To minimize your chance of atherosclerosis and heart disease you need to keep your total cholesterol low and your HDL high. Just having a good HDL is not sufficient to protect you from heart disease.

If you want to reduce your risk to near zero then:

• Keep your total cholesterol below 150
• Keep your HDL above 45
• Keep your LDL below 80

The cooperative lipoprotein phenotyping study

A good example of why just focusing on your HDL ratio is insufficient can been seen in the data from the cooperative lipoprotein phenotyping study. This study of 6,859 Americans was one of the first to show that coronary heart disease was not just correlated with high total cholesterol but also inversely correlated with high HDL.

In this study we can clearly see that those with a high total cholesterol and high HDL are at higher risk of heart disease than those with low total cholesterol and low HDL. And the lowest risk is for those with low total cholesterol and high HDL.

However because this study was done in America LDL less than 140 is considered to be low, so we don’t see what the impact of exceptionally low LDL levels would be.

The china study

To examine the impact of even lower cholesterol levels we can look at epidemiological studies in other countries, the most famous of which is probably the china study. In China where the average total cholesterol is 127 the risk of dying from heart disease is considerably less than in the US and is some areas the risk is near zero.

If we look at the areas with extremely low mortality rates from ischemic heart diseases we see two things:

• The majority have total cholesterol lower than 150
• Of those with total cholesterol greater than 150 (but less than 182) the majority have high HDL (>48)

In fact Dr William Castelli (former director of the Framingham study) noted that no one who maintained a cholesterol level lower than 150 in Framingham has had a heart attack.

Heart Attack Proof

The standard recommendation from the American Heart Association is to keep your total cholesterol below 200 mg/dL in order to lower your risk of heart disease – despite the fact that one in four heart attacks occur in people in the 180 to 210 range. One reason that this higher number is chosen is because this number is still attainable by people on a standard American diet and they do not believe that the dietary changes necessary to reach a lower more protective number would be acceptable to most Americans.

They may well be correct, however a number of medical professionals now believe that we should provide people with the information not just to reduce their heart attack risk, but to eliminate it. This includes people like Caldwell B. Esselstyn (author of Prevent and Reverse Heart Disease) his son Rip Esselstyn author of The Engine 2 Diet and T. Colin Campbell (author of The China Study).

Personally I am choosing to virtually eliminate the chance of heart disease by adopting a healthy plant-based diet.

References

HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study
Castelli et al. 55 (5): 767. (1977)

The China Study II (1989)
Monograph on Chinese ecological study