I finally got around to reading the American Dietitian Association’s 2009 position paper on vegetarian and vegan diets. Wow, a lot of bad news for veg*ans, especially those of the non-asterisked persuasion.

But I wouldn’t worry too much about it. Based on the multiple pleas for vegans and vegetarians to seek professional nutritional counseling, I figure this position paper is just one big scare tactic to drum up business for dietitians.

For anyone who hasn’t read the whole thing, here are the highlights:

The variability of dietary practices among vegetarians makes individual assessment of dietary adequacy essential. In addition to assessing dietary adequacy, food and nutrition professionals can also play key roles in educating vegetarians about sources of specific nutrients, food purchase and preparation, and dietary modifications to meet their needs.
(p. 1266)

Vegans and some other vegetarians may have lower intakes of vitamin B-12, calcium, vitamin D, zinc, and long-chain n-3 fatty acids.
(p. 1267)

Studies have found that although isolated soy protein can meet protein needs as effectively as animal protein, wheat protein eaten alone, for example, may result in a reduced efficiency of nitrogen utilization. Thus, estimates of protein requirements of vegans may vary, depending to some degree on dietary choices. Food and nutrition professionals should be aware that protein needs might be somewhat higher than the Recommended Dietary Allowance in those vegetarians whose dietary protein sources are mainly those that are less well digested, such as some cereals and legumes.

Cereals tend to be low in lysine, an essential amino acid. This may be relevant when evaluating diets of individuals who do not consume animal protein sources…

Because of lower bioavailability of iron from a vegetarian diet, the recommended iron intakes for vegetarians are 1.8 times those of nonvegetarians.

Whereas vegetarian diets are generally rich in n-6 fatty acids, they may be marginal in n-3 fatty acids. Diets that do not include fish, eggs, or generous amounts of algae generally are low in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fatty acids important for cardiovascular health as well as eye and brain development. The bioconversion of alpha-linolenic acid (ALA), a plant-based n-3 fatty acid, to EPA is generally less than 10% in humans; conversion of ALA to DHA is substantially less. Vegetarians, and particularly vegans, tend to have lower blood levels of EPA and DHA than nonvegetarians.

The Dietary Reference Intakes recommend intakes of 1.6 and 1.1 g ALA per day, for men and women, respectively. These recommendations may not be optimal for vegetarians who consume little if any DHA and EPA and thus may need additional ALA for conversion to DHA and EPA.

The iron in plant foods is nonheme iron, which is sensitive to both inhibitors and enhancers of iron absorption. Inhibitors of iron absorption include phytates, calcium, and the polyphenolics in tea, coffee, herb teas, and cocoa.

The bioavailability of zinc from vegetarian diets is lower than from nonvegetarian diets, mainly due to the higher phytic acid content of vegetarian diets. Thus, zinc requirements for some vegetarians whose diets consist mainly of phytate-rich unrefined grains and legumes may exceed the Recommended Dietary Allowance. Zinc intakes of vegetarians vary with some research showing zinc intakes near recommendations and other research finding zinc intakes of vegetarians significantly below recommendations.
(p. 1268)

Foods such as soybeans, cruciferous vegetables, and sweet potatoes contain natural goitrogens. These foods have not been associated with thyroid insufficiency in healthy people provided iodine intake is adequate.

Some studies suggest that vegans who do not consume key sources of iodine, such as iodized salt or sea vegetables, may be at risk for iodine deficiency, because plant-based diets are typically low in iodine. Sea salt and kosher salt are generally not iodized nor are salty seasonings such as tamari.
(p. 1268 - 1269)

Calcium intakes of lacto-ovo-vegetarians are similar to, or higher than, those of nonvegetarians, whereas intakes of vegans tend to be lower than both groups and may fall below recommended intakes. In the Oxford component of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford) study, the risk of bone fracture was similar for lacto-ovo-vegetarians and meat eaters, whereas vegans had a 30% higher risk of fracture possibly due to their considerably lower mean calcium intake.

In addition, some studies show that the ratio of dietary calcium to protein is a better predictor of bone health than calcium intake alone. Typically, this ratio is high in lacto ovo-vegetarian diets and favors bone health, whereas vegans have a ratio of calcium to protein that is similar to or lower than that of nonvegetarians.

The bioavailability of calcium from soy milk fortified with calcium carbonate is equivalent to cow’s milk although limited research has shown that calcium availability is substantially less when tricalcium phosphate is used to fortify the soy beverage.

Oxalates in some foods, such as spinach and Swiss chard, greatly reduce calcium absorption, making these vegetables a poor source of usable calcium. Foods rich in phytate may also inhibit calcium absorption.

Low vitamin D intakes, low serum 25-hydroxyvitamin D levels, and reduced bone mass have been reported in some vegan and macrobiotic groups who did not use vitamin D supplements or fortified foods.

The vitamin B-12 status of some vegetarians is less than adequate due to not regularly consuming reliable sources of vitamin B-12. Lacto-ovo-vegetarians can obtain adequate vitamin B-12 from dairy foods, eggs, or other reliable vitamin B-12 sources (fortified foods and supplements), if regularly consumed. For vegans, vitamin B-12 must be obtained from regular use of vitamin B-12-fortified foods, such as fortified soy and rice beverages, some breakfast cereals and meat analogs, or Red Star Vegetarian Support Formula nutritional yeast; otherwise a daily vitamin B-12 supplement is needed. No unfortified plant food contains any significant amount of active vitamin B-12. Fermented soy products cannot be considered a reliable source of active B-12.

Vegetarian diets are typically rich in folacin, which may mask the hematological symptoms of vitamin B-12 deficiency, so that vitamin B-12 deficiency may go undetected until after neurological signs and symptoms may be manifest.
(p. 1269)

Pregnant vegetarians receive statistically lower levels of protein than pregnant nonvegetarians; and pregnant vegetarians receive statistically higher levels of carbohydrates than pregnant nonvegetarians.

No research was identified that focused on macronutrient intakes among pregnant vegans.

Key nutrients in pregnancy include vitamin B-12, vitamin D, iron, and folate whereas key nutrients in lactation include vitamin B-12, vitamin D, calcium, and zinc.

The following micronutrients had lower intake among vegetarians than nonvegetarians: Vitamin B-12; vitamin C; calcium; and zinc.

In addition, one study reported that lower B-12 levels are more likely to be associated with high serum total homocysteine in lacto-ovo-vegetarians than low meat eaters or omnivores. Whereas zinc levels were not significantly different between nonveganvegetarians and nonvegetarians, vegetarians who have a high intake of calcium may be at risk for zinc deficiency (because of the interaction between phytate, calcium, and zinc).

Birth Outcomes. Four cohort studies were identified that examined the relationship between maternal macronutrient intake during pregnancy and birth outcomes such as birth weight and length. None of the studies focused on pregnant vegans.

Limited evidence from seven studies (all outside the United States) indicated that the micronutrient content of a balanced maternal vegetarian diet does not have detrimental outcomes for the health of the child at birth. There may be, however, a risk for a false positive diagnosis of Down syndrome in the fetus when maternal serum free beta-human chorionic gonadotropin and alpha fetoprotein levels are used as markers in vegetarian mothers.
(p. 1270 - 1271)

No studies included in the evidence-analysis examined vitamin D status during vegetarian pregnancy. Iron supplements may be needed to prevent or treat iron-deficiency anemia, which is common in pregnancy.

DHA also plays a role in pregnancy and lactation. Infants of vegetarian mothers appear to have lower cord and plasma DHA than do infants of nonvegetarians. Breast milk DHA is lower in vegans and lacto-ovovegetarians than in nonvegetarians. Because of DHA’s beneficial effects on gestational length, infant visual function, and neurodevelopment, pregnant and lactating vegetarians and vegans should choose food sources of DHA (fortified foods or eggs from hens fed DHA-rich microalgae) or use a microalgae-derived DHA supplement. Supplementation with ALA, a DHA precursor, in pregnancy and lactation has not been shown to be effective in increasing infant DHA levels or breast milk DHA concentration.

The safety of extremely restrictive diets such as fruitarian and raw foods diets has not been studied in children. These diets can be very low in energy, protein, some vitamins, and some minerals and cannot be recommended for infants and children.

Soy formula is the only option for nonbreastfed vegan infants. Other preparations including soymilk, rice milk, and homemade formulas should not be used to replace breast milk or commercial infant formula.

Solid foods should be introduced in the same progression as for nonvegetarian infants, replacing strained meat with mashed or pureed tofu, legumes (pureed and strained if necessary), soy or dairy yogurt, cooked egg yolk, and cottage cheese.

Little information about the growth of nonmacrobiotic vegan children has been published. Some studies suggest that vegan children tend to be slightly smaller but within the normal ranges of the standards for weight and height.

Vegan children may have slightly higher protein needs because of differences in protein digestibility and amino acid composition.
(p. 1271)

Key nutrients of concern for adolescent vegetarians include calcium, vitamin D, iron, zinc, and vitamin B-12. Being vegetarian does not cause disordered eating as some have suggested although a vegetarian diet may be selected to camouflage an existing eating disorder. Because of this, vegetarian diets are somewhat more common among adolescents with eating disorders than in the general adolescent population.
(p. 1271 - 1272)

With aging, energy needs decrease but recommendations for several nutrients, including calcium, vitamin D, and vitamin B-6 are higher.

Cutaneous vitamin D production decreases with aging so that dietary or supplemental sources of vitamin D are especially important. Although current recommendations for protein for healthy older adults are the same as those for younger adults on a body weight basis, this is a controversial area. Certainly older adults who have low energy requirements will need to consume concentrated sources of protein.

Research is needed on the relation between vegetarian diet and [athletic] performance.

Vegetarian athletes may have lower muscle creatine concentration due to low dietary creatine levels. Vegetarian athletes participating in short-term, high-intensity exercise and resistance training may benefit from creatine supplementation. Some, but not all research suggests that amenorrhea [loss of menstruation] may be more common among vegetarian than nonvegetarian athletes.
(p. 1272)

Not all aspects of vegetarian diets are associated with reduced risk for heart disease. The higher serum homocysteine levels that have been reported in some vegetarians, apparently due to inadequate vitamin B-12 intake, may increase risk of CVD [cardiovascular disease] although not all studies support this.

Several studies have reported lower blood pressure in vegetarians compared to nonvegetarians although other studies reported little difference in blood pressure between vegetarians and nonvegetarians.

Variations in dietary intake and lifestyle within groups of vegetarians may limit the strength of conclusions with regard to the relationship between vegetarian diets and blood pressure.
(p. 1273)

Among survivors of early stage breast cancer in the Women’s Healthy Eating and Living trial, the adoption of a diet enhanced by additional daily fruit and vegetable servings did not reduce additional breast cancer events or mortality over a 7-year period.

Although there is such a variety of potent phytochemicals in fruit and vegetables, human population studies have not shown large differences in cancer incidence or mortality rates between vegetarians and nonvegetarians.
(p. 1274)

A pooled analysis of 13 prospective cohort studies reported a high dietary fiber intake was not associated with a decreased risk of colorectal cancer after accounting for multiple risk factors.

Although very little data exist on the bone health of vegans, some studies suggest that bone density is lower among vegans compared with nonvegetarians. The Asian vegan women in these studies had very low intakes of protein and calcium. An inadequate protein and low calcium intake has been shown to be associated with bone loss and fractures at the hip and spine in elderly adults. In addition, vitamin D status is compromised in some vegans.

Results from the EPIC-Oxford study provide evidence that the risk of bone fractures for vegetarians is similar to that of omnivores. The higher risk of bone fracture in vegans appeared to be a consequence of a lower calcium intake.

Although excessive protein intake may compromise bone health, evidence exists that low protein intakes may increase the risk of low bone integrity.
(p. 1275)

Poor vitamin B-12 status has been linked to an increased risk of dementia apparently due to the hyperhomocysteinemia that is seen with vitamin B-12 deficiency.
(p. 1276)

Food and nutrition professionals have an important role in providing assistance in the planning of healthful vegetarian diets for those who express an interest in adopting vegetarian diets or who already eat a vegetarian diet.
(p. 1277)

It may be small consolation at this point, but the ADA does say veg*anism might be good for your heart. Problem with that is, correlation does not imply causation and it’s arguable that good hearts are what lead people into veganism. Diabetes and obesity are also cited as plagues that veg*ans may be less likely to suffer. So if you can dodge nutritional deficiency long enough to reach heart attack age, you might be better off than all those SAD folk.

But aside from one paragraph on dementia that is a mixed bag for veg*ans, the ADA’s position paper doesn’t look at how vegan nutrition affects brain health. My experience tells me that when veganism goes after you, it doesn’t bother with those purely mechanical organs — it goes straight for the brain.

Your hearts are strong… but watch your minds.