Loma Linda University study finds correlation between vegan diets and lowered risk of prostate cancer

[Stan]

Linda University study finds correlation between
vegan diets and lowered risk of prostate cancer

Finding published in the American Journal of Clinical Nutrition

 

LOMA LINDA, CA, January 12, 2016 – A recent study out of the Loma Linda University Adventist Health Study-2 (AHS-2), published in the American Journal of Clinical Nutrition, shows that vegan diets may present a lower risk of prostate cancer. This lower estimated risk was seen in both white and possibly black vegan subjects.

This study aimed to examine the association between dietary patterns (nonvegetarian, lacto-ovo-vegetarian, pesco-vegetarian, vegan, and semi-vegetarian) and prostate cancer incidence among 26,346 male participants of the Adventist Health Study-2.

According to the American Cancer Society, prostate cancer accounts for 27% of all incident cancer cases among men and is the second most common (noncutaneous) cancer among men. The relation between diet and prostate cancer is still unclear. Because people do not consume individual foods but rather foods in combination, the assessment of dietary patterns may offer valuable information when determining associations between diet and prostate cancer risk.

According to the study director, Dr. Gary Fraser, “These analyses provided evidence that subjects adhering to a vegan diet experienced about 1/3 lower incidence of prostate cancer than those preferring a nonvegetarian diet. Vegan diets differ from other vegetarian and nonvegetarian diets by the absence of dairy and eggs, as well as greater intake of most fruit, vegetables, nuts, and legumes.”

The study population consisted of male participants in the AHS-2. These subjects were aged ≥30y at enrollment and members of the Seventh-day Adventist Church who lived in the United States or Canada. Enrollment commenced in February 2002, and at completion (December 2007), more than 96,000 participants had completed the lengthy lifestyle questionnaire.

The full article, entitled “Are strict vegetarians protected against prostate cancer?” can be found in the 2016 vol. 103 no. 1 153-160 edition of the American Journal of Clinical Nutrition, available at: http://ajcn.nutrition.org.

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About Loma Linda University Health

Loma Linda University Health includes Loma Linda University's eight professional schools, Loma Linda University Medical Center's six hospitals and more than 900 faculty physicians located in the Inland Empire of Southern California. Established in 1905, Loma Linda University Health is a global leader in education, research and clinical care. It offers over 100 academic programs and provides quality health care to 40,000 inpatients and 1.5 million outpatients each year. A Seventh-day Adventist organization, Loma Linda University Health is a faith-based health system with a mission "to continue the teaching and healing ministry of Jesus Christ."

[Gregory Matthews]

Here is that abstract, as published in the professional journal:

Background: According to the American Cancer Society, prostate cancer accounts for ∼27% of all incident cancer cases among men and is the second most common (noncutaneous) cancer among men. The relation between diet and prostate cancer is still unclear. Because people do not consume individual foods but rather foods in combination, the assessment of dietary patterns may offer valuable information when determining associations between diet and prostate cancer risk.

Objective: This study aimed to examine the association between dietary patterns (nonvegetarian, lacto-ovo-vegetarian, pesco-vegetarian, vegan, and semi-vegetarian) and prostate cancer incidence among 26,346 male participants of the Adventist Health Study-2.

Design: In this prospective cohort study, cancer cases were identified by matching to cancer registries. Cox proportional hazards regression analysis was performed to estimate HRs by using age as the time variable.

Results: In total, 1079 incident prostate cancer cases were identified. Around 8% of the study population reported adherence to the vegan diet. Vegan diets showed a statistically significant protective association with prostate cancer risk (HR: 0.65; 95% CI: 0.49, 0.85). After stratifying by race, the statistically significant association with a vegan diet remained only for the whites (HR: 0.63; 95% CI: 0.46, 0.86), but the multivariate HR for black vegans showed a similar but nonsignificant point estimate (HR: 0.69; 95% CI: 0.41, 1.18).

Conclusion: Vegan diets may confer a lower risk of prostate cancer. This lower estimated risk is seen in both white and black vegan subjects, although in the latter, the CI is wider and includes the null.

 

 

[Green Cochoa]

According to an article to be found from last year, giving some data from the AHS-2 study, other cancers, like colorectal cancer, are higher in vegans (Tufts University Health & Nutrition Letter, 2015).  To quote a portion of the article:

Overall, vegetarians of all types were at 22% lower risk than non-vegetarians. But the scientists said they were surprised at the variation among vegetarian lifestyles. Compared to non-vegetarian participants, pescovegetarians were 43% less likely to develop such cancer. That risk was significantly lower even than vegans (16% lower than non-vegetarians), lacto-ovo vegetarians (eating dairy and eggs, 18% lower), and semi-vegetarians, defined as eating meat or fish once a week (8% lower). 

Obviously, then, unless one chooses to each some flesh foods in the form of fish, the best vegetarian diet in terms of certain cancers is that of the lacto-ovo vegetarian. This backs up what Mrs. White taught us so long ago.

Reference

Tufts University Health & Nutrition Letter. July 2015, Vol. 33 Issue 5, p3, 1 p.

[Gregory Matthews]

So, what should one do with the above:  [Note:   I refer to my post and not the one by Green.]

1) We must remember that correlation does not indicate cause.  To suggest that correlation indicates cause is a common mistake that many make which can easily be shown to be false. 

2) NOTE that the above states that the relation between diet and prostate cancer remains unclear.  IOW there still may exist other confounding factors which are involved and one should be careful as to any claims made related to diet and prostate cancer.

3) It is interest that the statistical significance, as reported in this study, exists only for whites and does not exist for black vegans.  This would indicate to me that there are other confounding factors that are  involved and have not been determined/considered in the study.

NOTE:  At this point it might be well for me to state my possible bias:

I am a life-long, fairly strict, lacto-ovo-vegetarian.

I happen to believe that such diets result in better health.

My wife is a strict vegan and due to that, the food served in our home has a decided vegan emphasis.