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My brief essay, “Meat is Brain Food,” on a New York Times Room for Debate brought about plenty of commentary from readers on strict animal-free vegan diets. While many were a little too specific for general interest, I’ve compiled here the seven most important vegan objections I’ve heard about the essay along with my nutrition and brain-health oriented answers.
There is much to be admired by vegan diets. Overall, vegans are much more mindful of nutrition than most people. They eat an awful lot of very good brain foods – nuts, berries, veggies (although processed soy foods are an area of concern, which I’ll save for another entry). Vegans have much lower levels of metabolic syndrome and obesity, and their diet is much easier on the planet than the Modern American Diet (MAD).
That said, we’ll have to agree to disagree on the point of animal based nutrients. I continue to believe that small amounts of the right kind of meats, fish and dairy will help ensure that you retain your sharp-thinking, even moods, fit body and overall health.
1. “Vegans get all the omega-3s they need from chia seed oil, flaxseed oil, linseed oil and walnuts.”
Chia, flax, linseed and walnuts are great brain foods for sure, but they lack the long-chain omega-3 fats that are the best documented for their mood-boosting benefits. Instead, they provide an omega-3, known as ALA. While your body converts ALA to the long-chained DHA and EPA omega-3s, you’re unlikely to get enough that way because the conversion rates are fairly low. Meat, eggs and fish are the only concentrated food sources of DHA and EPA omega-3s. Studies show that vegans have lower tissue levels of DHA and related sphingolipids that are important for the brain and also for many vegans and vegetarians the omega-3 to omega-6 ratios is 1:10, higher than desired (traditional diet are about 1:2).
2. “The vegan diet provides iron through spinach, kale, and beans. Compared to these plant foods, meat is an inferior source of iron on a per-calorie basis, and therefore unnecessary.”
Insufficient iron is the most common nutritional deficiency in the U.S., which is a big problem, since the parts of the brain related to memory, learning and mood are also the parts with the highest concentrations of iron. One trouble is that body absorbs less iron from plants, supplements and iron-fortified foods such as cereals. So iron deficiency can occur even among people who consume the recommended daily amount. Other molecules in plants like phytates and polyphenols interfere with iron absorption, as can calcium supplements.
The iron from animal sources, on the other hand, is special. It is a highly absorbable variety called “heme-iron,” which directly supplies the body with iron more efficiently. There is actually a different transporter in the gut for heme-iron. Additionally, meat also helps the body absorb iron from plant foods. For concentrated, easily absorbed sources of iron, it is hard to beat clams or beef. Liver is the best source. A half dozen clams or a few ounces of liver pate provides the entire 18 mg of daily recommended amount of iron for adult women. To get that much iron from kale, you’d have to eat 18 cups of chopped kale per day. That’s why eating high iron combos like a few ounces of grass-fed beef along with a serving of kale or a steamed clams and a spinach salad a few times a week ensures that you get enough iron in your system.
3. “Vegans don’t need to consume eggs, milk and fish for Vitamin D, since the body produces Vitamin D through exposure to ultraviolet sunlight. Just 10 minutes of sunlight per day, without sunscreen, gives most people all the Vitamin D they need.”
Sunlight is wonderful, but most people don’t get enough. Vitamin D deficiency - associated with depression, dementia and many other maladies -is widespread in the U.S. population. Once contributor is that people don’t eat enough seafood. Fatty fish is best dietary source of Vitamin D, with oysters a close second. Just four or five oysters can provide the entire recommended daily allowance of Vitamin D. People who don’t like fish may try to substitute eggs and milk, but both foods have very little Vitamin D.
4. “If blood tests show that you’re not B12, Vitamin D or iron-deficient, then there’s no reason to compromise a vegan diet by eating oysters, clams, liver and other animal food sources of these nutrients.”
Foods are not supplements. Eating choices that overtime lead to deficiencies concern me. Whole foods contain many nutrients, not just one or two, and they interact with each other in beneficial ways, such as the way beef helps the body absorb the iron in kale. Even if you test well for one nutrient or another, by avoiding animal derived foods entirely, you miss out on the top food sources of DHA and EPA fats, vitamin B12, vitamin D, and trace nutrients like selenium and zinc. There are vegan substitutes for most nutrients, but it can difficult and expensive for many people to get the right balance with them. The most recent large study of vegan and vegetarian diets found that the majority of the men were B12 deficient.
5. “One of the benefits of eating meat is said to be “conjugated linoleic acid” or CLA, which is only found in animal sources. But there are contradictory studies about CLA. Some say CLA is good, some say it’s bad. Vegans go without CLA entirely, proving that CLA is not necessary for a healthy diet.”
CLA may not be an essential nutrient, but it is a very interesting fat with likely health benefits. The bench science and animal model data regarding these and other benefits of CLA is incredible. The human data, which tests the supplement version, is admittedly not as impressive. I’m also persuaded by the data that shows that CLA may increase blood flow to the brain and protect brain cells. There are two recent studies of interest, a link between more CLA and a lower risk of developing diabetes and a very interesting human study looking at CLA concentrations in fat tissue and the risk of a first heart attack. For more about CLA, take a look at this piece, which also links to the study abstract.
6. “Vegans don’t need to get Vitamin B12 from meat if they take B12 supplements.”
I prefer food sources to synthetic vitamins. There is, after all, nothing “natural” about supplements. There is a lot we don’t know about how supplements of all kinds interact with the body, and whether they provide the same exact benefits as the natural nutrients they substitute for. We do know, however, that our bodies are the products of thousands of years of evolution. Until the rise of the Modern American Diet (MAD) in the last century, that long evolutionary process was fed entirely with whole, natural foods. I’m also worried about studies that continue to show risks of taking supplements like the recent Iowa Women’s Health Initiative data showing an increased risk of death for women who take multivitamins. As stated in a commentary on this data in The Archives of Internal Medicine: “We cannot recommend the use of vitamin and mineral supplements as a preventive measure, at least not in a well-nourished population.” For individuals choosing veganism for moral reasons, you must take a B12 supplement to make up for a nutrient deficiency in your diet.
7. “Grass-fed beef is not that different from all other kinds of beef. It is expensive, bad for the planet and has been associated with heart disease and cancer risk.”
Grass-fed beef hasn’t been studied enough to see its health effects when compared with factory-farmed beef. But there are several significant differences in the nutritional quality of grass fed beef – notably a better mix of fats, a better ratio of omega-3 to omega-6 fats and increased quantities of antioxidants like vitamins E and beta-carotene. Another indicator is that in countries where traditional grass-fed cattle are the only sources of beef and dairy products, heart disease rates are lower. CLA, mentioned above, is found in concentrations 300 to 500 percent higher in grass-fed beef.
As for the links to heart disease and cancer, these tend to be for higher levels of consumption – like 1.5lbs/week of red and processed meats. And the link is not as clear in the scientific data as one would think. Dietary cholesterol consumption is not the problem it is often made out to be. Most foods high in cholesterol content -- like shrimp, eggs, and grass-fed beef --offer lots of brain nutrients, low calories and are very satiating. Grass-fed beef is not as tough on the environment as the feed-dependent factory farmed beef, but there is no doubt that beef is still very energy intensive to produce – one reason it should be expensive. In general, most Americans eat too much of the wrong kind of beef. They’d be better off – and so would the environment – if they ate about half of much beef, and if the beef were grass-fed.
