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Studies Compare Pima Indians in U.S. and Mexico

Two independent studies published 12 years apart in the journal Diabetes Care evaluated the possible impact of the environment on the prevalence of obesity and diabetes in Arizona’s Pima Indians, a group with the highest reported prevalence of obesity and non-insulin-dependent diabetes mellitus. Data were collected on a population of Pima ancestry living in a remote mountainous location in northwestern Mexico, living a markedly different, “traditional” lifestyle in comparison to the Pima people of Arizona.  In the 1994 study, measurements of weight, height, body fat, blood pressure, plasma levels of glucose, cholesterol and HbA1c were obtained in 19 women and 16 men and compared with Pimas of the same sex, age, and diabetes status living in Arizona.  The study found that Mexican Pimas were lighter and shorter with lower BMIs and lower plasma total cholesterol levels than Arizona Pimas.  Only two women (11%) and one man (6%) had diabetes, contrasting with the expected prevalence of 37% and 54% in female and male Arizona Pimas, respectively. Twelve years later, the 2006 study reflected the same: significantly lower incidences of obesity and diabetes in the populations living in Mexico and leading a traditional lifestyle. The Mexican Pimas also enjoyed higher levels of physical activity than their U.S. Pima counterparts.
Diabetes Care 1994 Sep; 17(9): 1067-74 (Ravussin et al.)
Diabetes Care 2006 Aug; 29(8): 1866-71 (Schulz et al.)

Higher Phenols Beneficial in Extra-Virgin Olive Oil

Oxidative DNA damage is one of the metabolic precursors to cancer and coronary vascular disease and phenols are organic compounds with antioxidant properties. A study conducted in Florence, Italy measured the oxidative DNA damage in ten healthy, post-menopausal women when they consumed olive oils with different concentrations of natural phenols. Subjects replaced fats and oils habitually consumed with the study oil (50g/d), which was either a high-phenol extra virgin olive oil (592 mg total phenols/kg) or a low-phenol extra virgin olive oil (147 mg total phenols/kg) for eight weeks in each period.  The study found that during treatment of high-phenol-EVOO, the average oxidative DNA damage was 30% lower than the average during low-phenol-EVOO treatment. Though the sample size was small, the study indicated that consuming an extra-virgin olive oil rich in phenols, particularly hydroxytryosol, may reduce DNA damage.
British Journal of Nutrition 2006 Apr; 95(4): 742-51 (Salvini et al.)

Vegetarian Diet Does Not Affect Growth & Development in Children

Data from the European Prospective Investigation into Cancer and Nutrition (the EPIC-Oxford study) shows no difference between age at first menstruation or adult height  (measures of growth and development) between lifelong lacto-ovo vegetarian and non-vegetarian women. While the researchers point out that adult vegetarians generally have a lower average BMI, growth and development does not seem to be affected.
Public Health Nutrition. 2005 Aug 1;8(7), DOI 10.1079/PHN2005730. (Rosell et al.)

More Beans, Fewer Heart Attacks

When traditional diets are abandoned, health often declines –as a Harvard School of Public Health study found in Costa Rica. Researchers matched 2119 people who had suffered a first acute myocardial infarction with a similar control group and assessed their diets. After adjusting for many factors, they found that consumption of 1 serving or more of dried beans daily was associated with a 38% lower risk of heart attack.
The Journal of Nutrition, July 2005; 135(7):1770-5 (Kabagambe et al.)

Blood Pressure and Vegetarian Diets

Lifestyle factors, particularly diet, play a major role in blood pressure regulation.  Randomized, controlled studies indicate that plant-based diets are associated with BP reductions in both normal and hypertensive individuals.  According to this literature review by the Physicians’ Committee for Responsible Medicine, observational studies show that BP levels tend to be lower in individuals following self-selected vegetarian diets.  These findings strongly suggest that individuals with high blood pressure or at risk for developing high blood pressure may benefit from following plant-based vegetarian diets.  
Nutrition Reviews.  January 2005; 63(1):1-8. [Berkow S et al.]

Vegetarian Diets and Pregnancy

Inadequate vitamin B12 during pregnancy is associated with birth defects including neural tube defects and it is known that vegetarians are at risk for developing a B12 deficiency because they do not consume animal products, which are the principle source of this nutrient.  Scientists in Germany compared 70 pregnant women who had been vegetarian or near-vegetarian for at least three years (including 27 lacto-ovo vegetarians and 43 “low meat eaters”) to a control group of 39 pregnant women eating an average Western diet. By testing the women’s blood three times during pregnancy, they concluded that serum B-12 levels of the lacto-ovo vegetarians were lowest, the low meat eaters in the middle and the control group highest. The authors urge that recommended dietary intake levels of B-12 for pregnant women be re-evaluated.
The Journal of Nutrition. December 2004; 134(12):3319-3326. [Koebnick et al.]

Nutrition for Vegetarian Athletes

Scientists at the University of British Columbia  reviewed possible mechanisms by which vegetarian dietary practices could theoretically influence athletic performance.  After considering many different factors, including protein levels, carbohydrates, iron, vitamin B-12, and creatine levels, the researchers concluded that “well-planned, appropriately supplemented vegetarian diets appear to effectively support athletic performance.” 
Nutrition.  July-August 2004; 20:696-703.  [Barr and Rideout]

Nutrition Transition in Mexico and Other Latino Countries


In the past, the most common nutritional problem in Latin American countries was undernutrition.  However, these countries have recently undergone a nutritional transition characterized by an increase in energy-dense diets and increase in the prevalence of noncommunicable chronic diseases (NCCD) such as obesity, type 2 diabetes, and high blood pressure.  Researchers reviewed the available literature to determine the characteristics of the nutrition transition with emphasis in data from Mexico, Brazil, and Chile.  They found that some countries in Latin America like Brazil, Mexico and Chile are suffering from increased prevalence of overweight, obesity and NCCD related to dietary changes such as increased consumption of higher energy-dense processed foods and decreased consumption of fruits and vegetables.  
International Life Sciences Institute, July 2004; 62(7)S149-S157 (Rivera J et al.)

Diets of Latin-American and African-American Women

University of Hawaii researchers surveyed 271 African-American women and 234 Latin-American women, and assessed their diets. They found that the African-American women consumed more calories and more fat, while the Latino women consumed more carbohydrates and more fiber. While the Latino women weighed less, they were perceived themselves as heavier and reported “greater body image dissatisfaction.”
Obesity Research. April 2004; 12(4):652-60 (Sánchez-Johnsen et al.)

More Acculturation, Fewer Fruits and Vegetables

Acculturation is the extent to which mainstream customs, beliefs, and practices are adopted by immigrants.  Researchers in Washington State recruited 1,689 adult Hispanic and non-Hispanic participants to investigate whether acculturation is a predictor of fruit, vegetable, and fat intake among Hispanics.  Using the National 5-A Day for Better Health program dietary assessment instruments, researchers determined that highly acculturated Hispanics in Washington State consume significantly fewer fruits and vegetables than less acculturated Hispanics. 
Journal of the American Dietetics Association, January 2004; 104:51-57 (Neuhouser M et al.) 

Type 2 Diabetes and the Vegetarian Diet

While there are currently few data specifically connecting vegetarian diets and diabetes prevention or treatment, it is known that many of the specific foods that make up a vegetarian diet have advantages in the treatment of type 2 diabetes.  These foods include whole grains, legumes, nuts, seeds, soy proteins, and plant sterols.  This summary article from researchers at the University of Toronto details the benefits of different plant foods, and concludes that evidence documented in both cohort studies and intervention studies show that vegetarian diets “can help reduce the risk of developing type 2 diabetes and cardiovascular disease—a major complication of type 2 diabetes.”
American Journal of Clinical Nutrition. September 2003; 78(suppl):610S–6S. [Jenkins D et al.]

Colon Cancer Increases as Mexican Diet Fades

Researchers in Los Angeles examined whether the changing incidence of colorectal cancer in their city’s Mexican-American population was due to changes in dietary practices in this group.  Cancer incidence and dietary intake data were obtained for over 35,000 Latinos of Mexican national origin – the largest sample of Mexican-origin Latinos of any such study in the US.  The incidence of colorectal cancer saw the greatest increase between the first and second generations.  Nearly all dietary changes due to acculturation also occurred between the first and second generations.  These findings suggest an association between colorectal cancer risk and certain dietary components. Higher intakes of alcohol and refined carbohydrates were major risk factors, and lower consumption of vegetables was a protective factor.
Nutrition and Cancer 2003, Volume 45, Issue 2 (Monroe et al.)