There is compelling evidence that vegetarian and vegans diets are healthier than those that include animal meat or animal products. (Find a brief overview of the literature here.) Furthermore, compelling evidence suggest that vegetarian or mostly vegetarian diets promote longevity. (And the evidence that eating processed meats is bad for you is overwhelming.)
The main types of vegetarian diets are:
Ovo-Lacto Vegetarainism- No meat but incluces eggs and dairy products;
Ovo Vegetarainism – No meat or dairy products but includes eggs;
Lacto Vegetarainism – No meat or eggs but includes dairy products;
Veganism – No meat or any animal products.
The main nutrional worries about plant-based diets are that they lack: 1) protein; 2) vitamin B-12; 3) omega-3 fatty acids; 4) calcuim; 5) iron; and/or 6) vitamin D and D2. For ovo, lacto, or ovo-lacto vegetarians, the response to these worries is straightforward; for vegans getting all your nutrients is somewhat problematic. Before I proceed, a disclaimer. I am not a physician, nutritionist, dietician, or any other kind of health professional. So don’t take what follows to be medical advice.
With the disclaimer in place, here are a few options for providing these nutrients:
For vegans sources of protein include: pumpkin seeds, peanut butter, hemp seed, almonds, pistachio nuts, flaxseed, tofu, oats, soybeans, and walnuts. Other sources of all eight types of essential amino acids: lupin beans, chia seed, amaranth, buckwheat, spirulina, and quinoa.
Vitamin B-12 – Eggs and dairy products provide B-12 for lacto-ovo vegetarians.
Omega-3 fatty acids – Plant-based sources of Omega-3 fatty acids include: soy, walnuts, pumpkin seeds, canola oil, kiwifruit, hempseed, algae, chia seed, flaxseed, echium seed and leafy vegetables like lettuce, spinach, cabbage and purslane. Olives and olive oil are sources of unsaturated fatty acids. Supplements which the human body uses to synthesize the long-chain n-3 fatty acids EPA and DHA are also available. (EPA and DHA can be obtained directly in high amounts from oily fish or fish oils for pescotarians. Note too that meat eaters generally don’t get enough omega-3 fatty acids.)
Calcium – Eggs and dairy products provide calcium for lacto-ovo vegetarians.
Vegans can get calcium from broccoli, bok choy, kale, calcium-set tofu, turnip greens, mustard greens, soybeans, tempeh, almonds, okra, dried figs, and tahini. In addition there are supplements and calcium fortified foods. (For more see the Vegetarian Nutrition Calcium Fact Sheet from the Academy of Nutrition and Dietetics.)
Iron – Vegetarian foods rich in iron include black beans, cashews, hempseed, kidney beans, broccoli, lentils, oatmeal, raisins, spinach, cabbage, lettuce, black-eyed peas, soybeans, many breakfast cereals, sunflower seeds, chickpeas, tomato juice, tempeh, molasses, thyme, and whole-wheat bread. Vegan diets are often higher in iron than vegetarian diets because dairy products are low in iron.
Vitamin D and D-2 – The human body generates vitamin D with sufficient and sensible exposure to ultraviolet (UV) light in sunlight. In addition, cow’s milk, soy milk and cereal grains may be fortified to provide a source of Vitamin D.
Note – To reiterate, animal product based diets are associated with all sorts of health problems and lack many essentail nutrients. Furthermore, there are both moral and environmental reasons recommending vegetarianism in addition to its health benefits. Non-human animal suffering underlies the moral reasons, and the catastrophic environmental impact of meat eating grounds the environmental argument.
FInally, at the Oldways Finding Common Ground conference in Boston, MA on November 17-18, 2015, a group of leading nutrition and food systems experts reached consensus on the following points of common ground about healthy eating, as outlined below (or download PDF here):
The overall body of evidence examined by the 2015 DGAC identiﬁes that a healthy dietary pattern is higher in vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); lower in red and processed meats; and low in sugar-sweetened foods and drinks and reﬁned grains. Additional strong evidence shows that it is not necessary to eliminate food groups or conform to a single dietary pattern to achieve healthy dietary patterns. Rather, individuals can combine foods in a variety of ﬂexible ways to achieve healthy dietary patterns, and these strategies should be tailored to meet the individual’s health needs, dietary preferences and cultural traditions. Current research also strongly demonstrates that regular physical activity promotes health and reduces chronic disease risk. (Source: 2015 DGAC summary wording)