Lauding plant-only diets as a magic bullet for health is an oversimplification – a vegan diet requires careful planning.
Spanish vegan vlogger Rawvana’s 3.3 million social-media followers tuned in one day to catch the 28-year-old instagrammed furtively eating fish in a restaurant. She later admitted a return to the sins of the flesh had been prompted by amenorrhoea – cessation of menstruation – and fatigue.
Finnish vegan blogger Virpi Mikkonen, 39, went from despising eggs as “the miscarriages of chickens” to reintroducing red meat to her diet, after concluding that veganism had brought on early menopause.
Dutch vegan social-media influencer Kasumi Kriss resumed meat and eggs after figuring that her four years on fruit and vegetables alone was causing her skin breakouts, negative thoughts and lack of energy.
Although the more knowledgeable in the vegan community pointed out that, as they often say on social media, these women weren’t doing veganism right, their experiences underscore how important it is to do your homework.
Read more: Should we still eat meat and dairy?
Like any diet, an all-plant one needs to be nutrient-balanced. Veganism itself doesn’t cause amenorrhoea, early menopause, depression or skin problems, but a poorly balanced vegan – or any other – diet can.
Most of the important nutrients found in meat, fish, eggs and dairy can be found in plant foods, but it takes careful balancing, can be costly and can also lead to undesirable consequences in other countries’ land use.
Among the few single plants that have the range of amino acids found in meat, which is protein-dense, the two stars are quinoa and moringa. Alas, many of the native South Americans for whom the nutty-flavoured quinoa seed has always been a dietary staple can no longer afford it because Westerners have so embraced it as to drive the price up beyond their pockets.
Moringa, fast bowling kale out as the new “superfood” craze, is less problematic. Drought-resistant and tough, it’s grown in many countries. But it’s still a speciality food and not widely available or well understood.
Other popular vegan substitutions have backstories that somewhat negate the loftier reasons for veganism. It takes 74 litres of water to produce a single glass of highly nutritious almond “milk”, yet more than 80% of all almonds are grown in drought-prone California. Cashews do much heavy-lifting in the vegan diet, including being ground up as delicious cashew “cream”, but the standard of living of the Indian workers who produce 60% of the world supply is a continuing cause for concern. European chefs are increasingly eschewing the heroically nutritious avocado because of its voracious water appetite and displacement of forests in North and South America where most Northern Hemisphere imports are grown. Even seemingly blameless and untrendy rice has a bad report card for its flood-based produce’s methane and nitrous oxygen emissions.
In short, it’s not just New Zealand dairy farmers in the Intergovernmental Panel on Climate Change’s sights as requiring major transformation in what, where and how they farm.
But if getting an adequate vegan diet is ethically challenging, it need not be nutritionally so.
Dietitian Jennifer Bowden says there are important caveats among the micro-nutrients. It is trickier to get two of the essential omega 3 fatty acids, most plentifully found in seafood: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). They can be found in algae, but like moringa, eukaryotic photosynthetic microalgae are yet to feature much in lunch boxes, cafe cabinets or supermarket aisles. Bowden says the best bet is to eat plant oils such as flaxseed, walnut, soy and canola. Although they don’t contain DHA or EPA, either, they do have alpha-Linolenic acid (ALA), which can be converted into the other two fatty acids in the body – but not efficiently.
The other elusive nutrient for vegans is vitamin B12, which – less than ideally for the committed clean eater – can only be consumed within vegan rules as a dietary supplement or through artificially fortified processed foods such as plant milks, yeast extracts or breakfast cereals.
Calcium isn’t as bioavailable through many plant foods as it is through meat and dairy, so vegans are usually advised to consider supplementation; likewise iodine.
Iron deficiency is less likely than previously thought in people cutting out meat, but it’s a pronounced risk factor in the young – especially young women – who can take their vegan diets to extremes.
Meat is already well down the list of iron sources in the New Zealand diet. Bowden says the last nationwide nutritional survey found the biggest sources were bread (12%) and breakfast cereals (10%), followed by vegetables, grains and pasta, then beef.
Adding a vitamin C-rich food, such as kiwifruit or citrus, to meals where the source of iron is, say, lentils, beans and nuts will make the iron more readily absorbable. Bowden says vegans would be wise to avoid drinking tea and coffee or eating bran with meals as the polyphenols and phytates present in them inhibit iron absorption.
Auckland dietitian Caryn Zinn has a cohort of clients who describe feeling less tired after giving up on their vegan diets. She blames the lack of vitamin B12 and iron, especially among teenage girls with high iron needs as a result of menstruation. Missing out on easily absorbable iron is a “potential disaster”.
Zinn says lauding plant-only diets as a magic bullet for health is an oversimplification. Researchers have often linked high plant consumption to what have come to be known as “blue zones” – population pockets around the world that appear to enjoy longer lives than their national cohort. The most famous blue-zone take-out message among nutritionists is the healthiness of the Mediterranean diet, which is typically low in meat protein and high in vegetables and legumes.
“A lot of people have this view of veganism with a bit of a halo around it,” Zinn says. “It plays on people’s emotions from an animal welfare and sustainability perspective, but saying animal versus plants and plants are better – it is just not true. If you look at those living in the world’s blue zones, they have a lot more going on than just low meat consumption. They eat non-processed wholefoods cooked from scratch, they enjoy a strong sense of community, they get out of doors and stay on the move.”
An apparent blue zone in Icaria, Greece, included 99% of men who were smokers. The apparent health of that cohort could have been down to “healthy volunteer” bias, in which people most apt to co-operate with a survey are less likely to be sick. Another blue zone in Sardinia appeared to reflect not an unusual number of very old people, but widespread old-age-benefit fraud.
The US city of Loma Linda, California, was yet another statistical marvel, but Newman says it’s simply a richer population than its surrounding cohort, and its overall longevity is nothing special compared with other similarly well-heeled populations.
Though Newman’s efforts to debunk the blue-zone theory have been controversial, he says it may be as meaningless to infer that smoking prolongs one’s life as to attribute longevity to specific food choices or calorie restriction alone. Typically, he says, the richer the population, the healthier and longer-lived.
The scientific consensus stands, he says, that a good diet, exercise, not smoking and attendant advice remain sound.
“Meat might be better because of micronutrients that aren’t easy to get from plants. To be vegan you have to be creative with your food and take a lot of supplements.”
Overall, says Katherine Black from the University of Otago’s department of human nutrition, a well-balanced vegan or vegetarian diet can provide all the necessary protein, fats, carbohydrates, vitamins and minerals for optimal health “but it depends on whether you put effort into finding out what foods to replace the food you do cut out. As with any diet, you have to make sure it is a varied diet and you are not substituting your animal products with sweet treats or chips.”
This article was first published in the August 24, 2019 issue of the New Zealand Listener.