Somewhat frequently I am referred patients who are “trying to go vegan”. I have been plant-based for more than 20 years, and coupled with my nerd-tastical propensities, I should be the perfect person support this endeavour. Be the motivation bettering health, climate change, animal cruelty, a recent cancer diagnosis or heart attack, plant-based diets are seen as the solution to many ills. But what surprises some is that I counsel certain people against veganism. Oui oui madames et monsieurs, you read that right: a card-carrying veg-head doctor does not think everyone should be plant-based.
I am going to break down why that is. Over a series of posts, I will dig into what plant-based diets are and how they tickle a variety of health parameters like disease reduction and management, nutrition, climate change, factory farming, community, and spirit. In each post, I will review the benefits of a plant-based diet and its shortcomings. I will also share a photo diary of what I eat and drink in a day so to humanize the elusive ‘how do you survive without meat?!’ herbivore diet. I do not espouse to make a case for or against plant-based diets but to present considerations and support you in selecting the best diet for you.
Now before getting into it, some rules of our playground. Firstly, this review is about non-pregnant adults. If you are a child, a teenager, or someone who is pregnant or trying to become so, this information is not specific enough. Please speak with a qualified healthcare professional to review ways of achieving your body's nutritional needs. Secondly, to achieve breadth I sacrificed some depth. In future postings I will tease out some of the more interesting nuances neglected. If there something in particular you'd like triaged to the top of that list, please reach out and let me know.
One of the larger totted trophies of plant-based diets is their potential for disease reduction. Be it cardiovascular woes like heart attack or stroke, metabolic struggles like obesity or diabetes, turbulent transitions of menopause, or the ever-dreaded cancer, plant-based diets statistically reduce burden and risk. So let us look at the numbers.
The numbers around plants and cardiovascular health are striking. Plant-based diets reduce coronary heart disease events by 40%, coronary heart disease by 32%, and reduce the risk of cerebral vascular disease by 29% (PMID: 28792455). They can reverse atherosclerosis (yes, I said reverse) and lower blood pressure. Plant-based diets will also lower blood lipids by similar amounts as statins but without the pesky, sometimes painful, side effects . The benefit so marked, in August of 2019, the Journal of the American Heart Association released a study that concluded, and I quote, "diets higher in plant foods and lower in animal foods were associated with a lower risk of cardiovascular [disease] and mortality in a general population" (PMID: 31387433). This statement is not lightly made; it is based on 29 years of data on more than 12 thousand people at risk for atherosclerotic disease. Proverbial. Mic. Drop. - Wait, do nerds get to drop the mic? Is it more apt to say calculator drop? Spectacles drop? - Proverbial. Calculator. Drop.
Getting beyond your heart and vasculature, eating a plant-based diet greatly impacts your weight and blood sugar regulation. Vegan diets reduce your risk of developing metabolic syndrome and type-2 diabetes by 50% (PMID: 28792455). Metabolic syndrome is shorthand for saying someone has hypertension (high blood pressure), central adiposity (the metabolically active and dangerous stomach fat), and insulin dysregulation (approaching or full-fledged diabetes). And while the studies are limited in size (meaning further research is required), plant-based diets can reduce and/or eliminate peripheral neuropathy in type-2 diabetics (PMID: 28792455). For those who are already diabetic, plant-based diets can reduce the amount of medication required to manage the disease (PMID: 16873779, PMID: 19339401).
Plant-based diets, when properly done, will reduce weight. I will get into what properly means in future postings but for now properly means a variety of whole plant foods and not an exchange of meat for processed carbohydrate and soy products. In several studies where vegan diets were compared to calorie-restriction diets, vegans lost more weight and felt more satiated (meaning they ate until they were full and were not restricted in how much they could eat) (PMID: 16873779, PMID: 16164885). People usually stare at me dumb-struck when I say they can lose weight and not count calories.
Vegan diets are studied in woman and there is benefit. Plant-based diets reduce female-specific cancers and menopausal unrest (PMID: 23169929, PMID: 29704911). Plant-based women have 34% lower rates of breast, cervical, and ovarian cancers. Furthermore, women who consumed a plant-based diet reported statistically significant less hot-flushes and other pesky experiences of menopause like insomnia and irritability. While there much nuance to explore here, sufficed to say the findings bode well for plant-based women.
Expanding to all people and cancer, a plant-based diet will reduce your risk of cancer by 15% (PMID: 26853923). This generalized reduction is seen even when factors are controlled for - factors like comparing groups of people with similar vegetable intake and other parameters like smoking, alcohol, and family history (PMID: 23169929). That risk reduction remains independent of the aforementioned factors is striking. The case has become so salient the World Health Organization acknowledges “[d]iets high in fruits and vegetables may have an independent protective effect against many cancers” and their dietary guidelines strongly encourage plant consumption and meat reduction (World Health Organization).
Here is where I transition into discussing shortcomings of plant-based diets. Given I will be discussing matters specific to vitamins and minerals tomorrow, let’s set aside malnutrition issues for the time being.
To start let’s discuss the numbers and research we’ve leveraged above. Most of these studies are observational meaning groups of people report their diet and health markers (like blood lipids) or health outcomes (like rates of cancer) are compared. This way appreciates humans as dynamic creatures and honours “real life” does not happen under strict and consistent laboratory conditions. While arguably more applicable, it assumes honest responses from the observed and sacrifices the control science relies on to get exacting answers. By extension it limits what we can know and how we can apply learnings. For example, we can say there is statistical correlation between vegan diets and not getting cancer, but we cannot say vegan diets causes you not to get cancer. It is also limited to the population studied. So if the observations were of Asian women, the results are arguably only applicable to Asian women.
We also need to look at the comparison groups. In the above studies, people self-identified as vegan/vegetarian are compared to people self-identified as “other”. “Other” can mean many different things ranging from the standard North American diet of browns and yellows (think bread, hamburgers, cheese, french fries) to a more balanced omnivore diet (think vegetables, fish, chicken, whole grains). I share this not to discount the benefit of plant-based diets, but to contextualize it. While scientists are adjusting now more than ever, historically far fewer studies compare benefits of herbivores to well-balanced omnivores. Not all research is inconsiderate but risk reduction numbers must be understood in this light: if you are switching from a brown and yellow diet you are going to realize full benefit of a vegan diet, but switching from a healthy omnivore diet, the benefit is (potentially) less.
Furthering the consideration of what “other” means, research shows the benefits of plant-based diet are not solely derived from meant-abstinence. Swapping your steak for a bagel will not afford you the bounty of health previously discussed. Independent of meat-eating status, plant consumption will reduce your risk for cardiovascular, metabolic, and cancerous disease (PMID: 24687909). It the volume of unprocessed, plant food consumed that garners a fair portion of benefit. While this gets more into nutrition (next blog post), giving up animal products only to replace it with processed carbohydrates and meat-alternatives is not beneficial to your health.
So far I have discussed some methodological issues with plant-based diet research and that it vegetables that confirm a lot a benefit as opposed to solely a meat-free diet. What about disease creation – does a vegan diet increase risk of disease? There are two instances where it may.
Firstly, gastrointestinal cancers. While vegans have a lower rate of cancer compared to healthy meat-eaters, they do have a higher risk of colorectal cancers when compared to pesco-vegetarians (those who eat fish but not meat) and lacto-ovo vegetarians (those who eat dairy and egg products but not fish or meat) (PMID: 25751512). When it comes to colorectal cancers, pesco-vegetarians have a risk reduction of 43%, lacto-ovo vegetarians of 18%, and vegans of 16%. So while vegans are better off compared to the average meat-eating bear, they are worse off compared to vegetarians that consume fish or animal byproducts like yogurt or eggs.
Secondly, there is an emerging connection between a vegetarian/vegan diet and depression (PMID: 30404246, PMID: 28777971, PMID: 12127390, PMID: 27884936). Research is still too scarce to be definitive yet rates of depressive symptoms seem to be higher in people on plant-based diets. The concern so great amongst mental health care practitioners it inspired researchers to investigate the matter. There are two things worth note. First, it may be attributable to a poor execution of a plant-based diet (PMID: 28777971) and not veganism itself. Secondly, researchers note plant-based diet and depression may be an example of a larger picture wherein depression correlates to food elimination and not exclusively veganism (PMID: 30404246). Regardless of the why, there is a association those considering a plant based diet should be aware of.
Phew, that a mouthful of a first post. Next posting I will excavate the macronutrition (fats, proteins, and carbohydrates) and mincronutriton (vitamins, mineral, antioxidants, etc.) of plant-based diets and here some delicious highlights: fiber should be more a focal point of your diet than protein and deficiencies of a vegan diet stretch beyond the expected vitamin B12 and calcium. Tune in 2 weeks: same bat time, same bat blog.