Revision as of 07:18, 1 March 2018

• work in progress*

Human beings need certain nutrients, not specific sources of those nutrients. Adequate nutrition deals with meeting nutritional needs in terms of essential fatty and amino acids, calories, and vitamins and minerals to avoid deficiencies that affect health in a clinically significant way. Where the question of adequate nutrition stops is at more speculative issues. Optimal nutrition picks up where adequate nutrition leaves off, with questions of ideal ratios between macro-nutrients and calorie sources, timing of meals, and other composition to achieve certain results like peak atheletic performance, disease prevention, or longevity.

The consensus among the overwhelming majority of dietetic organizations is that a properly planned vegan diet, with B-12 supplements and other considerations, is adequate for human beings during all stages of life.

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood and for athletes.[1]

This is echoed by nutritional recommendations of major governmental bodies, including the oft criticized USDA (which has animal agriculture industry ties, and it in no conceivable sense biased in favor of veganism).

Vegetarian* diets can meet all the recommendations for nutrients. The key is to consume a variety of foods and the right amount of foods to meet your calorie needs. Follow the food group recommendations for your age, sex, and activity level to get the right amount of food and the variety of foods needed for nutrient adequacy. Nutrients that vegetarians may need to focus on include protein, iron, calcium, zinc, and vitamin B12.[2]

• This is followed by extensive recommendations for lacto-ovo vegetarians and for vegans; the USDA considers both forms of vegetarianism.

Criticism of consensus tend to be either overtly conspiratorial, or vague fear-mongering claims that there isn't enough evidence which is in itself a claim without evidence-- and one that implies either irresponsibility and stupidity of professionals or a conspiracy, because obviously they agree there is enough evidence as reflected by consensus.

Critics may also Cherry-pick the DGE (German Nutrition Society) which released a more critically worded 2016 position paper[3], ignoring the fact that the recommendations are focused on sensitive groups within the context of German culture and food availability: for example, in Germany (due to ill-conceived EU regulations on organic labeling) the overwhelming majority of vegan substitutes like plant milks are not properly fortified with well studied vitamins and minerals, but with unusual forms of plant extracts (See discussion in comments[4]). The position does not state that a vegan diet is inherently inadequate or unhealthy, and to the contrary outlines specifically HOW to get the necessary nutrients in table 2: Potential critical nutrients in a vegan diet and vegetable nutrient sources. The general sentiment of the position paper is that they do not believe that people are competent, and it is necessary that fortified foods and vegan specialty foods and supplements be more reliable and widely available to reduce risk of inadequate nutritional status on a population level. The tendency of German vegans to favor organic and want to avoid all supplements seems also to be a major concern.

Difficulty

Animal products have many drawbacks, introducing unwanted substances and disease risk factors to the body, and optimal nutrition status may be more difficult to achieve on a diet including them. However, they are rich in a number of nutrients, particularly minerals and amino acids, which make adequate nutritional status somewhat easier (in much the same way that taking a multivitamin does). I.O.W. You might have a higher risk of a heart attack, but less risk of ever being low in B-12.

A properly planned vegan diet (with B-12 supplements) is perfectly adequate, but the nutritional knowledge to plan a vegan diet is neither intuitive nor instinctual, and where cultural eating patterns can help pass on that knowledge through the brute force of surviving traditions that didn't make people sick (at least while they were young), there have never been any large and long-standing vegan cultures to adopt dishes from (likely due to the B-12 issue).

While the developing industry of meat replacements and other animal product replacements will in time solve this issue through fortification, unfortunately not all animal product replacements are properly fortified, and some are offensively inadequate alternatives.

In the mean-time, vegans need to familiarize themselves with the basics of nutrition and the nutrients of concern so that they can overcome the cultural shortcomings by properly planning their diets. There is a learning-curve to veganism, both in understanding the basics of nutrition and learning to prepare nutritious foods that you like and will reliably eat, and particularly for groups that are high-risk (or lazy eaters) it is probably better to go slowly and get accustomed to e.g. lacto-vegetarianism or pescetarianism before moving on and excluding all animal foods.

Genetic Variation

There are a number of aspects of genetic variation that are incredibly important to the topic of adequate nutrition, but not in the way critics want them to be.

A properly planned vegan diet, actually followed (easier said than done, for some), is as suitable to anybody as an omnivorous diet would be; with millions of vegans there has never been a credible case study of anybody who could not be vegan because they needed some nutrient not available from a balanced vegan diet with B-12 supplementation as recommended.

Recommended daily intakes are based in a broad array of information for most nutrients, both human and non-human animal data (like closely related rodents and other primates), and include information we gained from developing TPN (Total Parenternal Nutrition, IV-nutrition based on a mix of fatty and amino acids, vitamins and minerals), along with studies of deficiencies which have in the past manifested in populations without access to adequate nutrition, and in vegans in the early days (who manifested with B-12 deficiency due to lack of supplementation).

While it remains possible that there is somebody out there who can not synthesize arachidonic acid or taurine (as in cats) due to spontaneous mutation, the risks are unmeasurable and astronomically low (and must be compared to the risks of consuming animal products). Given the evidence, a more probable explanation for cases of failure on a vegan diet is nutritional ignorance or lax practice: however, that does not mean condemnation is in order, because both of these are typical. The likely difference is genetic: some people thrive with otherwise inadequate diets, or due to innate food preferences (like a preference for vegetables and savory foods, rather than sweets) stumble on adequacy by mere accident of nutrient density of the foods they naturally prefer.

There ARE practical issues that make it very difficult to follow a balanced vegan diet like food allergies (particularly to nuts and legumes) and intolerances to fiber, but these are immediately manifest and would be known by anybody prior to going vegan.