Debunking a Plant-Based Diet

The health sphere holds many conflicting opinions over plant based diets, with some touting it the fountain of youth or the cure to cancer, whilst others remain fearful of near-certain malnourishment. So, what’s the truth? This blog aims to tackle some of the most common misconceptions held.

Myth: A vegan diet is always healthy.

To begin, let’s clarify the difference between veganism and plant based diets.

Veganism stems from a moral belief that is usually held for reasons of animal rights or environmental concern, in which one abstains from consuming or using any animal products; this includes eating meat, dairy, eggs, fish, and even honey.

A strictly whole-foods, plant-based (WFPB) diet happens to be suitable for vegans, as it is composed solely of unprocessed plant based food groups, including fruit, vegetables, legumes, whole grains, nuts and seeds.

A person may choose a WFPB diet solely for health reasons, or as a healthy choice to support their ethical vegan lifestyle. Vegan diets do not necessarily have to be health promoting, in fact technically speaking you could eat a diet composed of nothing but French fries, Coca Cola and Vegan Magnums and call yourself a Vegan. A vegan diet specifies what’s removed from the diet, whereas a WFPB diet focuses on all the healthy foods included in it.

For the sake of this article, when discussing the health implications of a ‘vegan diet’, I am referring toWFPB diets.

Myth: Vegans are all skinny and malnourished.

Whilst the majority of people are concerned with losing weight these days, it is often considered that vegans might be underweight due to nutritional inadequacies in their diet. Whilst neither following a vegan nor omnivorous diet can entirely determine whether somebody is under or overweight, looking at large population studies on vegans shows a remarkable trend.

In the Adventist Health Study-2, comprised of 22,434 men and 38,469 women, mean BMI was seen to be lowest in vegans (23.6 kg/m²) and incrementally increased as diets included higher amounts of animal foods, with non-vegetarians holding a mean BMI of 28.8 kg/m². In this study population, who held many similar lifestyle habits, such as regular exercise, abstinence of coffee and alcohol, and an inclination towards healthy eating, with non-vegetarians eating relatively low-meat diets, the vegans were in fact the only group who fell into the normal BMI bracket.¹

The EPIC-Oxford study which compared 37,875 ethical vegans, vegetarians, pescatarians and meat-eaters also found the vegans to have the lowest mean BMI of all groups, again falling into the healthy normal range. The meat eaters in this study were relatively health conscious, consuming a daily average of 18.8g of fibre versus the vegan’s 27.05g of fibre, thus indicating that their diets contained a substantial amount of plant matter, and they were not simply gorging on McDonalds every meal.² It is to be noted that the vegans included in this study did not appear to be following an optimal diet, since a WFPB diet would typically include between 40-50g/fibre a day.³ Still, at all ages vegans had a lower BMI than the meat eaters by 1-2kg/m².  The less striking differences between dietary groups compared to the Adventist Health Study-2 may be attributable to the latter vegan group consuming a much healthier diet than the Oxford vegan group; with an average of 46.7g of daily dietary fibre indicating a far greater consumption of unprocessed plant foods.^2,4

In fact, more than twenty studies have shown vegans to be leaner than other dietary groups, with lower BMIs and lower body fat percentages.⁵

We may wonder whether the lower BMIs are attributable to starvation on the part of the vegan groups; perhaps eating nothing but plant foods inevitably leads to calorie restriction? A 2017 randomised controlled trial put 33 overweight or obese patients on a WFPB diet and concluded that this research achieved greater weight loss at 6 and 12 months than any other trial which does not limit energy intake or mandate regular exercise. At twelve months, mean reduction in BMI for the WFPB group was an extraordinary 4.2 (±0.8) kg/m² BMI points.⁶

What conclusions can we take from these findings? It appears that whilst a vegan diet may not be associated with being underweight, it might well be protective against the sweeping trend towards obesity.

Myth: Animal protein is necessary for human health.

Due to decades of industry advertising, most of us have been well and truly indoctrinated with the message that it’s necessary to eat animal products to live a long, healthy life. However, the American Dietetic Association, the largest dietetic association in the world has a different opinion, stating that “appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases.”⁷

It seems increasingly major bodies are recognising both the adequacy and the advantages of a plant-based diet for us, and the environment. We can even see Canada going as far as removing the dairy group from their 2019 Food Plate, and offering the advice to “Choose protein foods that come from plants more often.” ⁸

The World Health Organisation asks that we decrease our consumption of saturated fats (largely found in animal foods, aside from tropical plants such as coconut) and increase consumption of “fruits and vegetables, and legumes, whole grains and nuts”.⁹  The UN goes as far as calling meat “the world’s most urgent problem” from the perspective of climate change, and praises those developing plant-based alternatives.¹⁰

So, what health benefits might expect to see on a strictly plant based diet? Looking again at the Seventh Day Adventists, we can see that the vegan group experienced a 15% lower overall mortality rate compared to meat eaters, with vegetarians and vegans enjoying lower risk of hypertension, type 2 diabetes, obesity, cardiovascular disease and certain cancers.¹¹

Myth: Milk is the only source of calcium.

Milk is absolutely not the only source of calcium, nor is it necessarily optimal for human health. Great plant based sources of calcium include broccoli, collard greens, tahini, legumes, nuts and seeds.

In the EPIC-Oxford Study, a 30% increase in bone fractures were seen in the vegan group compared to other dietary groups. However, around 45% of these vegans had calcium intakes below 525mg per day, whilst less than 6% of those in other dietary groups had intakes this low. Whilst the current RDI for calcium in Australia is around 1000mg for adult men and women (increasing during pregnancy and over 50 years old in women), when only vegans meeting 525mg per day of calcium or above were included, fracture rates were the same as for meat eaters, and actually slightly lower than in fish eaters and vegetarians.¹²  This highlights the importance of following a well-planned WFPB diet.

Calcium is far from the only nutrient involved in bone health; consult with a holistic health practitioner, such as myself, or dietitian to learn more.

Myth: Iron Deficiency Anaemia is inevitable.

One of the most common stereotypes of a vegan or vegetarian seems to be that they’re universally anaemic due to a red-meat deficiency. Whilst from personal observation, I can report that women of all dietary preferences frequently struggle with maintaining optimum iron levels, it is important to understand how to optimise iron intake on a plant based diet.

It is true that non-haem iron (that found predominantly in plant matter) is less well absorbed than the haem iron (found predominantly in animal matter). (N.B. I say predominantly as there are now vegan burgers containing haem extracted from the roots of soy plants.) However, whilst better absorbed, haem iron may act as pro-oxidant, increasing oxidation of LDL cholesterol and consequently atherosclerosis. High iron intakes and excess iron in the body have also been associated with Alzheimer’s, Parkinson’s diseases, arthritis, Type 2 DM, colorectal and other cancers.^13,14

Non-haem iron absorption is better regulated by the body, with increased absorption taking place when iron levels are low and vice versa.^15,16

With our typical Western lifestyles, it is important to realise that our tea and coffee consumption is deleterious to iron absorption, and these should be enjoyed away from our meals. Vitamin C rich foods can increase non-haem iron absorption by up to 6x and should be enjoyed with every meal; this could include squeezing lemon or lime on your food, including berries with your oatmeal, or eating capsicum with your tofu salad.^3,16  Consuming onions and garlic with grains or legumes can even increase the availability of iron and zinc considerably.¹⁷  Legumes are a wonderful way to increase iron intake, with their non-haem ferritin iron shown to be highly absorbable.¹⁸

Due to the difference in absorption of non-haem iron, the amount of iron vegans should aim for is actually higher than the typical RDI, with vegan dietitian Brenda Davis proposing 25mg of iron as a healthy target when taking into account both promoting and inhibiting dietary factors.

Myth: A vegan diet will take care of itself.

Whilst a well-planned vegan diet is undoubtedly adequate and even promoting of good health, if you don’t know what you’re doing, you can easily run into a few problems. I should know, as I made almost every mistake in the book when I first made my transition from an omnivorous diet onto a vegan diet. It is really important to understand where you’re getting your protein, iron, zinc, calcium, B12, Omega 3, iodine and everything else. There are so many examples of bad-vegan diets to follow on the internet; ones which are not remotely nutritiously adequate and bound to lead to all sorts of problems in the long run. Just because you see an Instagram model promoting nothing but drinking green juice all day long, does not mean this is healthful. These diets are not going to be sustainable for your health, and you won’t be doing the vegan message any favours.

There are many wonderful resources to help, many of which will be linked to from my website in future blog posts. However, it is often best to get a bit of outside expert assistance, and there are some great dietitians or naturopaths (such as myself) out there who are very familiar with a vegan diet and can make sure you’re on the right track. With a bit of practice, there is no reason why you cannot enjoy excellent health on a vegan diet.

Diet is not everything. I firmly believe that nutrition is one of the greatest tools we have to good health, but it is not everything. In Dean Ornish’s work where he documented incredible reversal of heart disease in his patients, halted prostate cancer growth and even telomerase extension, he used plant based diets in conjunction with lifestyle modifications; these included meditation, social support, and exercise.^19,20,21  Nutrition is extremely important, but it’s best enjoyed alongside other health promoting lifestyle choices for optimum results.

Myth: B12 is not necessary to supplement

It is. Very necessary. Just because a few outliers have managed to avoid supplementation, does not mean this is true for the general population. Supplement- please.

Myth: Infants and children cannot be vegan.

There are certain times of life when the stakes are higher when it comes to health- these include during pregnancy, infancy and childhood. The American Dietetic Association is very clear in its position when it states that “Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.”²² The words I’d like to emphasise are “well-planned”; this does not mean you can remove animal products from the diet and just hope for the best. In a future article, I’ll go into more details over the potential benefits of a plant based diet for all stages of life; but for now, it is highly recommended that if you intend to raise your children on a plant based diet, that you consult with a plant based dietitian. A trained professional with a specialised knowledge of plant-based diets can ensure that you’re providing your children with everything they need to grow up healthy and strong.

References

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17. Gautam S, Platel K, Srinivasan K. Higher Bioaccessibility of Iron and Zinc from Food Grains in the Presence of Garlic and Onion. J Agric Food Chem. 2010;58(14):8426-8429. doi:10.1021/jf100716t
18. Theil EC, Chen H, Miranda C, et al. Absorption of iron from ferritin is independent of heme iron and ferrous salts in women and rat intestinal segments. J Nutr. 2012;142(3):478-483. doi:10.3945/jn.111.145854
19. Ornish D, Scherwitz LW, Billings JH, et al. Intensive Lifestyle Changes for Reversal of Coronary Heart Disease. JAMA. 1998;280(23):2001. doi:10.1001/jama.280.23.2001
20. Ornish D, Weidner G, Fair WR, et al. Intensive lifestyle changes may affect the progression of prostate cancer. J Urol. 2005;174(3):1065-1070. doi:10.1097/01.ju.0000169487.49018.73
21. Ornish D, Lin J, Chan JM, et al. Effect of comprehensive lifestyle changes on telomerase activity and telomere length in men with biopsy-proven low-risk prostate cancer: 5-year follow-up of a descriptive pilot study. Lancet Oncol. 2013;14(11):1112-1120. doi:10.1016/S1470-2045(13)70366-8
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