Large studies of the health of Adventists began 61 years ago. They were funded because Adventists were an especially informative population on which to study the effects of diet and lifestyle. Interestingly, a key reason for this is that the church does not require (with a few exceptions) a certain lifestyle, but rather strongly recommends it.
Members interpret healthful living very differently, according to their circumstances, and so church members eat in very diverse ways, but with an overall bias toward fewer animal products. This sets up an ideal research situation, where some eat very differently from the average American, and others fall closer to the mainstream North American diet.
The countercultural diets that many Adventists follow have become of great interest, as we and others confirm that they are particularly healthful and much more suited to the health of the planet. In general, studies that relate specific nutrients to mortality, cancer, heart attack, etc., have become somewhat controversial recently, as results often seem to disagree—certainly as reported in the public media without any consideration of study quality. Results pertaining to broad patterns of eating, however, are much more consistent and compelling. This includes diets that trend toward the vegetarianism that many Adventists have followed now for more than 100 years.
More than 400 reports about the health of Adventists have appeared in the medical literature. Before publication, all manuscripts go through a rigorous peer-review process by academics from other (non-Adventist) institutions, where there is no bias toward Adventist dietary positions. So let’s look at the broad themes from all these reports, with an emphasis on more recent results.
Studies comparing the risk of dying among Adventists and non-Adventists of the same ages have been unequivocal. Adventists are at lower risk, whether they were from California in the 1960s (55 percent lower), across the U.S. currently (35 percent lower, similar in Black and White Adventists), from the Netherlands (55 percent lower), or from Norway (35 percent lower in those converting to Adventism before age 35; less in older converts). When we compared nonsmoking non-Adventists to Adventists, similar-sized benefits remain.
Our studies of the health effects of religious practice do find some benefits—particularly with respect to mental health. Those benefits seem to be in addition to dietary effects. In California all this translates to an Adventist longevity advantage of 7.3 years in men and 4.4 years in women. If you are a vegetarian Adventist, these differences swell to 9.5 and 6.1 years. Moreover, an AHS-2 substudy indicates that Adventists also enjoy better mental and physical quality of life, at least through the eighth decade (statistics not available at higher ages). This has led to Loma Linda, representing California Adventists, being identified as a zone of exceptional longevity.
Compared to other Americans, Adventists also experience reductions in risk of all cancers lumped together (by 30 percent); fewer cancers (specifically of the rectum, breast, and lung); also, a reduction of cardiovascular disease (by about 50 percent) and cardiovascular death.
Consideringthe studies that compare Adventists to non-Adventists, it seemed likely that diet was one important cause of the differences seen. But this would be more convincing if more details were available. An obvious dietary candidate was the vegetarian habits of many Adventists, and we had the opportunity to compare the health experience of tens of thousands of vegetarian to nonvegetarian Adventists. Again, the answers are quite clear.
Taking vegetarian Adventists as a group (i.e., putting together vegans, those who eat dairy and eggs, those eating fish as the only flesh food, and those eating meat less than once per week) and comparing to those who eat red meat and/or poultry at least once each week, we find clear and substantial advantages to the vegetarians. This is with respect to overweight, risk of diabetes, blood pressure levels, blood cholesterol levels, total mortality (about 12 percent less at any particular age), total cancer, cancers of the colon and rectum, and cardiovascular disease (men more clearly than women). Interestingly, it was only the vegans (i.e., strict vegetarians) who had less prostate and probably less breast cancer than nonvegetarian Adventists. Further work about other cancers is underway.
These are challenging tests, as comparing Adventist vegetarians to Adventist nonvegetarians does not contrast a great difference in meat consumption, as the nonvegetarians are mainly low-meat consumers—less than two ounces a day on average (red meats and poultry); yet differences in health experience are found. This is why comparisons in the previous section between all Adventists and all non-Adventists, however, are usually even greater.
What is it about vegetarians that leads to these advantages? We have only a few probable answers as yet, but they are intriguing. Vegetarian Adventists are very different from nonvegetarian Adventists in ways apart from meat consumption. They eat more nuts, fruits, vegetables, legumes, and whole grains, and less animal products, sweets, refined grains, snack foods, and calorie-containing beverages.
Interestingly, even lacto-ovo vegetarians consume only 60 percent of the quantities of dairy as do nonvegetarians. We have recently shown that these different dietary intakes are reflected in the bodily composition of Adventist vegetarians and nonvegetarians, as they have different concentrations of many fatty acids in adipose (body fat) tissue, different levels of most carotenoids in the blood, and different levels of soy isoflavones and the amino acid 1-methylhistidine (from animal muscles) in the urine.
Particular food items appear to be more influential than others when trying to explain the vegetarians’ health advantages. We now believe that frequent consumption of small quantities of nuts is probably causally related to substantially less heart disease (associations found in many studies following our initial report); and that red meat consumption is probably causally related to risk of colorectal cancer, cardiovascular disease, and probably risk of diabetes.
Dairy is a tricky case, being associated with less colorectal cancer, but initial indications are of greater risk of prostate and breast cancers (two hormone-related cancers). Finally, initial findings appear to show that higher tomato intakes (perhaps especially cooked or canned) are associated with lower rates of prostate and ovarian cancers.
It is important to note that in AHS-2 we have also checked all these results in Black Adventists. In no case do we find a clear difference in results according to race. The advantages that we report appear to be equally available to Black and White church members.
A recent report from AHS-2 received much attention in the press, as we found strong evidence that eating a good breakfast and avoiding calories later in the day (thus a longer overnight fast) was associated with lower body weights. These were relatively small effects that built year on year to become 10 to 12 pounds less weight in older years when an epidemic of obesity results in so many Americans being much heavier than ideal.
What is the bottom line? Although by no means alone, Adventists are distinguished among religions by having a particularly strong focus on healthful living. We also believe that we are created and designed by a loving God, who may hope that His creation will be well cared for.
Nevertheless, as Adventists we do not believe that healthful living is a test of religious purity. Decisions that faithful members make on these things can be complicated and depend on many factors often unknown to others. As we consider these matters we can now be satisfied in this age of science that careful peer-reviewed scientific research shows that the dietary advice we received 150 years ago almost certainly does extend life; avoids premature cardiovascular deaths; and decreases risk of many, if not most, of the chronic disorders that impair quality of life in the latter years of so many Americans. Our Adventist health emphasis is now, more than ever, still well worth sharing!
Gary E. Fraser, MBChB, Ph.D., M.P.H., a specialist in internal medicine, cardiovascular disease, and nutritional epidemiology, was until recently the principal investigator of Adventist Health Study-2 at Loma Linda University in California.