An introductory note from DrKF – For some folks, being vegan or vegetarian is a calling; more than a simple dietary decision. Once upon a time, my significant other was a vegetarian. For him, (ie. his body type, dietary preferences and limited exercise habits) being vegetarian was a shoe-in for diabetes. I was newly enrolled in school and challenged him on his diet frequently. In hindsight, I deeply regret my approach. Dan’s choice to avoid meat was a calling, not a health decision…and there is much I now know I could do to support him in manifesting an extremely healthful diet. Fast forward to now, at the clinic, we’re actually super supportive of reducing excess meat intake, with some caveats of course. – DrKF
The vegan diet is seemingly everywhere at the moment. The convergence of interests from celebrity personalities (even the 2020 Golden Globes menu was all-vegan) and ecological proponents has created a perfect storm for it to surge in prominence. We do get many inquiries about vegan diets, for reasons that include ethical, health and environmental, including by many people who simply want to reduce their meat intake, aka ‘flexitarian.’
But are vegan diets really a good idea for all? Read on to find out…
What does the science say on vegan diets?
It’s true that most of the science indicates that, in general, avoiding high meat consumption, and especially processed meat such as bacon, hot dogs, and sausages, is associated with reduced risk for major diseases like type 2 diabetes, heart disease, cancer, even overall mortality. Not all studies agree on the benefits of an outright vegan diet, though – some (including a 2019 review article) found no risk difference between vegans and omnivores for total heart disease and all-cause mortality risk. A recent study, looking at a large cohort – the EPIC Oxford study – even found a higher incidence of stroke in vegans and vegetarians than meat eaters.
It’s hard to draw conclusive recommendations from these data, unfortunately, since they indicate association only, not causation. There are also potential confounding factors in the large association studies – vegans and vegetarians are more likely to be health conscious in general, working to maintain a healthier weight and exercising frequently. There are very few intervention trials done on vegan diets and they use only a small number of participants for a short duration, using surrogate disease markers such as HbA1c, or C-reactive protein, rather than actual disease outcomes or mortality. It’s not just vegan diets that fall into difficulty in studies, though, these research challenges apply to dietary investigations in general.
Potential benefits of vegan diets:
Higher intake of healthful plant foods, whether vegan, vegetarian, or ‘flexitarian’, means an increased intake of phytonutrient and fiber compounds. Phytonutrients and fiber, typically through interaction with our all-important gut microbiome, generate beneficial compounds that our bodies absorb and use.
These are strongly associated with protective health effects in published systematic reviews and in the longest-running cohort studies such as the Harvard-based Nurse’s Health Study, Atherosclerosis Risk in Communities Study, and Health Professionals Follow-Up Study. We strongly agree that eating more whole and varied plant foods is nearly always beneficial.
For those who eat very little plant food to begin with, transitioning to a healthy vegan diet may be an improvement if it is associated with increased consumption of beneficial non-processed vegetables, fruits, legumes, whole grains, nuts and seeds, and reduces consumption of pro-inflammatory processed meats, refined grains, and sugars.
From an ecological perspective, it’s clear that reducing global beef consumption overall is an important factor in reducing carbon emissions. Vegan and vegetarian diets are effective at reducing environmental impacts in high-income countries that consume more meat products. However, it’s interesting to note that in countries with low or moderate consumption of animal-source foods, there is very little improvement in environmental impact with replacing those animal foods with plant foods.
Potential risks of vegan diets
Vegan diets are not a health panacea, however. There are several reasons why:
Many vegans still eat unhealthful foods
Poorly implemented vegan diets can also be too high in sugars, other refined carbohydrates, and processed foods that have been shown to worsen metabolic state and the risk for type II diabetes, heart disease and cancer (even among vegetarians and vegans). Both the Nurse’s Health Study and the Health Professional’s Follow Up Study data show that beneficial associations do not hold for unhealthful plant food choices like juices, refined grains, sweetened beverages, pizza and desserts.
On that note, the rising popularity of vegan processed foods such as the Beyond Burger and Impossible Burger deserve a mention – read our blog “Faux Meats: Good for the Planet – But What About Your Health’ to see why we don’t recommend choosing these processed vegan foods.
Nutrient deficiencies are more likely
There is a risk for nutrient deficiencies in improperly-planned vegan diets, especially B12, calcium, iron, zinc, certain amino acids, and omega-3 fatty acids. These risks are greater during certain life stages such as pregnancy, infancy and childhood, and for older individuals. The effects of these nutrient deficiencies are often not seen for several years, and can include general symptoms of fatigue, malaise, poor growth or development in children, mood and psychological changes. B12 deficiency, in particular, can cause potentially-irreversible neuronal damage. The relationship of these symptoms to dietary deficiency is often missed.
We do routinely see the negative nutritional effects of long-term vegan diets in clinic. It’s not the only dietary pattern to generate nutrient deficiencies, for sure, but it’s one with a significantly higher degree of risk.
Potential case-by-case issues
Vegan diets still contain foods that can cause issues for some individuals – gluten and soy in particular are common problem foods. Celiac disease, Non-Celiac Gluten Sensitivity, and soy sensitivity can all mean adverse health reactions to eating these foods. Vegan diets are also high in FODMAP foods which can aggravate symptoms of Small Intestinal Bacterial Overgrowth, an increasingly common problem. Individuals with eating disorders would not be good candidates for a vegan diet either, since the additional food restrictions can worsen existing restrictions and disordered eating patterns.
Will I benefit from a vegan diet? It depends
These potential benefits and risks highlight a supremely important point, one which cannot easily be investigated well by current research methods – that the benefits and risks of any dietary change are different for each of us. They depend on life stage, existing diet, nutrient status, health condition, food access, and ability to properly plan nutrient intake.
Nearly half of all American adults have at least one chronic disease – these are conditions that are responsible for 7 out of every 10 deaths and 75% of healthcare costs. There is no one diet that will solve these issues. Arguably, the development of population-wide nutrition advice has gone hand-in-hand with increased rates of obesity and chronic disease.
We need a new approach – an understanding that nutrition can and must be personalized. The same dietary approach will not have the same effect from one person to the next.
We also need to evolve how we study nutrition, since food is inherently complex. No single diet is implemented by everyone in the same way, and dietary patterns contain thousands of unique variables that are affected by food choices/availability and nutrient variability in foods, and that interact with each other – often synergistically, sometimes antagonistically. We need a way to capture research that addresses personalized nutrition.
Our four staff nutritionists are members of the American Nutrition Association, the professional home for personalized nutrition and oversight of the Certified Nutrition Specialist Credential.
What should I do?
If you’re not currently vegan or vegetarian, and currently consume high levels of meats and few plant foods, then adding healthful plant foods to your diet and reducing meat consumption is most likely a very good idea. We don’t recommend for health reasons, however, that you need to be completely meat free. To reduce your ecological impact, consider meats and fish with lower carbon footprints, such as pork, poultry and fish – these foods have similar carbon footprints to vegetarian and vegan foods.
Challenge for 2020! To get more phytonutrients into your diet, eat 8-12 servings of colorful plant foods per day. Consider our 6-day at-home healthRESET program (suitable for vegans, vegetarians, flexitarians and omnivores) for additional detoxification support and to reset your eating patterns for the New Year.
We are also strongly in favor of tracking the impact of any dietary changes on important health parameters. These include blood biomarkers such as blood glucose control, lipids and inflammation. Symptoms too – some individuals get increased abdominal symptoms when they add foods such as legumes, fruits and certain vegetables. Working with a specialist in personalized nutrition can help you identify how to evaluate and navigate that.
If you are still determined to adopt a vegetarian or vegan lifestyle, then we highly recommend getting some reliable advice for planning personalized nutrient intake to avoid deficiencies and customizing the diet to suit your unique needs. And keep a close eye on how you do healthwise.