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Vegetarian Diets and the Incidence of Cancer

Using data from the Adventist Health Study-2 researchers from Loma Linda University in California looked at the relationship between vegetarian dietary patterns and the incidence of cancer in a low risk population. In this prospective study, vegetarian diets appeared to confer protection against cancer. A vegan diet appears to have the overall lowest risk of cancer and female-specific cancers; a lacto-ovo-vegetarian pattern provided greatest protection from gastrointestinal cancers.
Cancer Epidemiol Biomarkers Prev. 2013; 22:286-294. (Tantamago-Bartley et al.)

Semi-Vegetarians Most Likely to Exhibit Eating Disordered Behavior

Researchers from Towson University and the University of Pennsylvania conducted two studies on a total of 486 participants to determine whether diet type (vegan, lacto ovo vegetarian, semi-vegetarian including pescatarians and red meat vegetarians, and omnivorous) was associated with eating disordered behavior including emotional  eating, restrained eating, and desire for thinness. They found that the semi-vegetarians were relatively the most disordered in terms of their food-related behaviors and attitudes. Vegans had the healthiest attitudes toward food, closely followed by vegetarians – a somewhat surprising result, given the inherent restrictions of the diets. The authors call for further research on the relationship between semi-vegetarianism and disordered eating.
Appetite. 2012 Jun;58:982-90. (Timko et al.)

Traditional Japanese Breakfast Foods Improve Glucose Tolerance

Researchers studied the effect of traditional Japanese breakfast foods on insulin sensitivity in a small sample of individuals with impaired glucose tolerance.  The group which ate foods such as natto (fermented soybeans) and viscous vegetables (such as Japanese yams and okra) for 2 weeks demonstrated improved insulin sensitivity, serum lipids, and oxidative stress compared to the control group.
British Journal of Nutrition. 2012 Apr;107(8):1184-1191. (Taniguchi-Fukatsu et al.)

B-12 Status and Vegans

Individuals who choose to follow a vegan diet are at increased risk for being deficient in vitamin B-12, which occurs in meaningful bio-available amounts only in animal foods.  This type of vitamin deficiency is very serious and can cause many irreversible health problems, yet vegans often don’t take B-12 supplements because they consider them “un-natural.” Polish scientists followed 20 healthy adult volunteers for five years after they switched from an omnivorous diet to a strict vegan diet. Ten consumed only natural products, while the other ten consumed foods fortified with B-12. Not surprisingly, B-12 serum levels were down in the natural group, but not in the fortified group.   
Acta Scientiarum Polonorum, Technologia Alimentaria April 2, 2012; 11(2):209-213. [Lisowska A et al.]

Risks of Iron Deficiency Equal Among Vegetarians and Omnivores

Researchers from Central Washington University and California Polytechnic State University compared the iron intakes and serum iron levels of 19 vegetarian college women with 20 non-vegetarian college women. They found that 66% of vegetarians and 65% of non-vegetarians failed to meet the recommended daily allowance of iron (14-18mg). Furthermore, there was no significant difference in serum iron levels between the two groups. In fact, both vegetarians and non-vegetarians had high rates of iron deficiency. These results suggest that while female college students have a high risk of iron deficiency, a vegetarian diet alone does not increase this risk.
Health. 2012 Mar;4(3):113-119. (Hawk et al.)

Vegetarian Diet Helps Maintain Good Mood

Researchers at Benedictine University in Illinois conducted a randomized control trial to determine the effects on mood of consuming a vegetarian diet, compared with an omnivorous diet or a meat-restricted fish diet.  Omnivorous diets are high in arachidonic acid (AA) and research has shown that high intakes of AA can promote changes in the brain that can disturb mood.  Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are fats found in fish which are thought to improve mood by opposing the negative effects of AA. This study randomly selected thirty nine omnivores and assigned them to either a group consuming meat, fish and poultry daily (OMN); a group consuming fish 3-4 times weekly but avoiding meat and poultry (FISH), or a vegetarian group avoiding meat, fish and poultry (VEG).  Mood was tested using the Profile of Mood States questionnaire and the Depression Anxiety and Stress Scales.  The study found that the VEG participants, who through the diet reduced their EPA, DHA and AA intakes, had mood scores that improved significantly after two weeks whereas OMN and FISH participants had mood scores that remained unchanged.  In conclusion, the results of this study suggest that restricting meat, fish, and poultry may improve some domains of short-term mood states in modern omnivores.
Nutrition Journal 2012 Feb 14;11:9 (Beezhold et al.)

Lacto-Vegetarian Diet Cuts Heart Risk

It is known that vegetarians have lower incidence of risk factors for coronary heart disease including lower low-density lipoprotein (LDL) cholesterol, lower prevalence of obesity, and healthier lifestyle overall.  It is hypothesized that this reduction in risk factors is due to the consumption of a primarily plant-based diet.  To test this idea, Swedish scientists asked 20 volunteers to switch from their usual omnivorous diet to a lacto-vegetarian diet (no meat, fish or eggs, but dairy is allowed) for a full year. Dietitians offered advice and cooking classes, and researchers took dietary surveys and blood samples at the start and every three months throughout the year. Subjects lost a significant amount of weight and significantly lowered their BMIs; they also significantly lowered their blood pressure, total cholesterol, and LDL cholesterol – all risk markers for coronary heart disease
Open Journal of Preventative Medicine. February 2012;2(1):16-22.  [Johansson et al.]

Raising Vegetarian Children

This literature review from University Hospital Ghent in Belgium weighed the risks and benefits of vegetarianism in children.  Childhood is a vulnerable growth period during which adequate nutrition is essential.  The study concluded that with regard to macronutrients and micronutrients, well-planned lacto-ovo vegetarian and vegan diets with proper supplementation can support healthy growth and development in children.  Children with more restricted diets are at greater risk for nutrient deficiencies and special care in vegan children should be taken to ensure adequate intakes of vitamin B12, calcium, zinc, and energy-dense foods containing quality protein.
European Journal of Pediatrics. December 2011; 170:1489-1494. [Winckel et al]

Less Diabetes Among Vegetarians

Researchers at Loma Linda University in California studied a group of healthy, non-diabetic people – 15,200 men and 26,187 women (17.3% blacks) – in the U.S. and Canada to determine associations between diet and diabetes. After collecting dietary and lifestyle data, the researchers divided the subjects into five groups: vegan, lacto-ovo vegetarian, pesco-vegetarian, semi-vegetarian, and non-vegetarian, then contacted all of them again after two years. They found that vegan, lacto-ovo and semi-vegetarian diets were protective against the development of diabetes, which had developed in 2.12% of non-vegetarians during this interval and that “in Blacks, the dimension of the protection associated with vegetarian diets was as great as the excess risk associated with Black ethnicity.”
Nutrition, Metabolism, and Cardiovascular Diseases. October 7, 2011. [Epub ahead of print] (Tonstad et al.)

Lower Incidence of Diabetes in Vegetarians

A 2011 study examined the relationship of diet to incidence of diabetes among Black and non-Black participants in the Adventist Health Study-2.  The study participants included 15,200 men and 26,187 women (17.3% black) living in the US and Canada who were free of diabetes. Participants provided demographic, anthropometric, lifestyle and dietary data, while a follow-up questionnaire two years later elicited information on the development of diabetes.  Participants were grouped as vegan, lacto ovo vegetarian, pesco vegetarian, semi-vegetarian or non-vegetarian (reference group). The questionnaire results showed that vegetarian diets (vegan, lacto ovo and semi) were all associated with a substantial and independent reduction in diabetes incidence.  Blacks have long been associated with having an increased risk for diabetes.  The results of this study showed that the protection provided against diabetes from the consumption of vegetarian diets was as great as the excess risk associated with Black ethnicity.
Nutrition, Metabolism and Cardiovascular Diseases 2011 Oct 7. (Tonstad et al.)

Vegetarians, Vegans and Blood Pressure

The goal of this study was to examine the relationship between vegetarian diet and blood pressure in Seventh-day Adventists.  Through food questions administered at clinic in churches across the USA and Canada, researchers from Loma Linda University studied data on 500 white Adventists, including vegasn, lacto-ovo vegetarians, partial vegetarians, and omnivores  The study found that vegetarians, and especially vegans, have lower systolic and diastolic BP and less hypertension than omnivores and that this difference is only partly due to their lower body mass.
Public Health Nutrition. October 2011; 15(10):1909-1916 [Pettersen B et al.]

Diverticular Disease and High-Fiber Vegetarian Diet

A study conducted by the University of Oxford Cancer Epidemiology Unit examined the associations of a vegetarian diet and dietary fiber intake with risk of diverticular disease. The participants included 47,033 men and women living in England and Scotland of whom 33% consumed a vegetarian diet.  After a mean follow-up of 11.6 years, there were 812 cases of diverticular disease, 806 admissions to the hospital and six deaths. After adjusting for confounding variables, vegetarians had a 31% lower risk of diverticular disease compared with meat eaters.  Similarly, there was also an inverse association with dietary fiber intake.  Participants who consumed 25.5 grams of fiber or more a day for women and 26.1 g/day for men had a 41% lower risk of diverticular disease compared with those consuming less than 14 g/day of fiber. 
British Medical Association 2011 Jul 19; 343:d4131 (Crowe et al.)