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Health Effects of Vegan Diets

A nationwide poll conducted in 2006 determined that 1.4% of the American population is vegan—they eat no meat, fish, dairy, or eggs.  Scientists at Andrews University in Michigan reviewed existing studies about veganism to assess the pros and cons of adopting such a diet.  Overall, vegans tend to have lower BMI, lower serum cholesterol, and lower blood pressure, decreasing their risk of developing cardiovascular disease.  However, because of the elimination of all animal products, vegans are at greater risk of certain nutritional deficiencies such as vitamins B12 and D, calcium, and omega-3 fatty acids.  It is suggested that vegans consume foods that are fortified with these nutrients or that they take appropriate supplements to prevent deficiencies.
American Journal of Clinical Nutrition.  May 2009; 89:1627s-33s [Craig WJ]

Low-Fat Vegan Diet May Be Most Effective in Controlling Type 2 Diabetes

Researchers from the George Washington University conducted a randomized, controlled trial on 99 participants with type 2 diabetes. 49 participants were randomly selected to follow a low-fat vegan diet, while the remaining 50 were to adopt a diet following the 2003 American Diabetes Association guidelines (“conventional diet”). The groups followed their assigned diets for 74 weeks. By the end of the trial, the researchers found that both diets had resulted in weight loss, improved glycemic control as measured by HbA1C, and a reduction in blood triglycerides. Once the results were controlled for medication adjustments, however, the low-fat vegan diet appeared to improve glycemic control and blood triglycerides more than the conventional diet. This study illustrates the physiological benefits of adopting a plant-based diet.
American Journal of Clinical Nutrition. 2009 May 1;89(suppl):1588S-96S. (Barnard et al.)

Diet & Cancer Risk in Asian-American Women

Researchers in Los Angeles conducted a study to evaluate how diet may affect the risk of breast cancer for Asian American women.  Those who adhered most closely to the factors of a Mediterranean Diet (lower intake of meat and starches and a higher intake of vegetables and legumes, including soy) had a 35% reduced risk of breast cancer compared to a Western diet or an ethnic diet with a higher intake of meat and starch.
American Journal of Clinical Nutrition. 2009 Apr; 89(4):1145-1154. (Wu et al.)

Med Diet: Keeping Your Brain Healthy

A study conducted by the Columbia University Medical Center examined the association between adherence to the Mediterranean diet and mild cognitive impairment (MCI) among 1393 multi-ethnic participants.  Using Cox proportional hazards, the association between adherence to the Mediterranean diet (0-9 scale) and the incidence of MCI, as well as the progression of MCI to Alzheimer’s disease was assessed.  The models were all adjusted for age, sex, ethnicity, education, genotype, caloric intake, body mass index, and duration between baseline dietary assessment and baseline dietary diagnosis.  The study concludes that a higher adherence to the Mediterranean diet correlates to a reduced risk of developing mild cognitive impairment and reduced risk of MCI conversion to Alzheimer’s disease.
Archives of Neurology 2009 Feb; 66(2):216-25 (Scarmeas et al.)
 

Nutrition Concerns for Vegetarian Athletes

Researchers from the University of Rome conducted a review of the recent literature surrounding the nutritional adequacy of vegetarian diets among athletes.  Although it remains unclear whether vegetarian diets are preferable to omnivorous diets for athletic performance, the data show that it is possible for vegetarian athletes to maintain good nutritional profiles. However, vegetarian athletes may have to be more vigilant about ensuring adequate calorie, Iron, Zinc, Vitamin D, and Vitamins B12 (cyanocobalamin) and B2 (riboflavin) intake, through supplementation if necessary. Additionally, creatine supplementation may benefit vegetarian athletes who engage in repeated bouts of short-term high-intensity exercise.
Sport- Und Präventivmedizin. 2009 Jan;39(1):20-24. (Borrione et al.)
 

Africans' Allergies Increase With Urban Diets

The prevalence of allergies has consistently increased in Africa over the past 7-10 years.  Studies have shown that as an African country’s gross national income increases, so does the link between IgE, skin reactivity to allergens and allergic symptoms. Whereas Africans in rural Africa seem to suffer less from allergies, people of African descent in affluent countries have a higher prevalence and greater severity of allergic symptoms compared with the natives of those host countries. A study conducted at Leiden University in the Netherlands has identified the shift to a more ‘urban diet’ as a marker for increased skin reactivity to allergens, and therein a compromiser to the immune system.
Current Opinion in Clinical Immunology. Oct. 2008 (Obeng et al.)

Less Acculturated Latinos Enjoy Better Diets

It is known that the healthfulness of the Latino diet deteriorates during the acculturation process, as Latino immigrants adopt the habits of their new culture.  A meta-analysis was conducted to review the literature available on the effect of acculturation on the Latino diet.  The analysis concluded that there was no relationship between acculturation and dietary fat intake or percent energy from fat, despite evidence that fat-related behaviors seem to differ between those who are less or more acculturated.  It also concluded that less acculturated Latin Americans consumed more fruit, rice, beans, and less sugar and sugar-sweetened beverages than more acculturated Latin Americans.
Journal of the American Dietetic Association, August 2008; 108:1330-1344 (Ayala G et al.)

Obesity in Nigeria: Current Trends and Management

Nigeria is facing an increasing prevalence of obesity, with a particularly strong occurrence in populations with hypertension and diabetes. A Nigerian study of these increases says that the rise of obesity rates can easily be attributed to rapid unplanned urbanization, change from local dietary pattern to western style diet which is driven by the proliferation of fast food outlets in major cities across the country. This study makes that connection.
Nigerian Medical Practitioner Vol. 54 No 1, 2008 (11-5). (Akpa et al.)

Vegetarians May Have Increased Risk of Bone Fracture

Researchers at Loma Linda University investigated a cohort of peri- and post-menopausal women over a period of 25 years to compare incidences of wrist fracture with diet type. They found that vegetarians who consumed low amounts of protein suffered the most wrist fractures. However, increasing levels of plant-based protein foods decreased risk by 68% and increasing meat intake decreased risk by 80%. These findings suggest that dietary protein plays a significant role in bone health among middle-aged and elderly females.
Public Health Nutrition. 2008 June 1;11(6):564-572. (Thorpe et al.)

Low Omega-3 Fatty Acid Status in Vegans

Researchers at the University of Vienna compared the ratio of omega-6:omega-3 polyunsaturated fatty acids (PUFAs) in omnivores, vegetarians, vegans, and semi-omnivores to assess essential fatty acid status as it relates to diet. They found that vegans had the highest average ratio of omega-6:omega3 PUFAs. High ratios are believed to be pro-inflammatory and may also contribute to tissue decline and neurological dysfunction. While the authors emphasize the need for further research on this topic, they also urge vegetarians and especially vegans to increase their intakes of omega-3 fatty acids from non-animal sources such as algae.
Annals of Nutrition & Metabolism. 2008 Apr;52:37-47. (Kornsteiner et al.)

Fruits, Vegetables, Fiber Decline with Latina Acculturation

A cross-sectional study conducted by the Population Research Center in Austin, Texas used data from the 2000 National Health Interview Survey and its Cancer Control Module to examine the association of diet with country of birth and language acculturation among 1,245 non-pregnant women of Mexican descent living in the US.  The study found that US-born women consumed fewer grams of fiber per day and a larger percentage of energy from fat than Mexican-born women.  Similarly, greater English language use was associated with decreased consumption of fiber. Researchers concluded that English-speaking, US-born women have a greater risk of declining dietary quality compared to Mexican-born women because the latter are more likely to retain some of their cultural (Mexican) eating patterns.
Journal of the American Dietetic Association; March 2008; 108(3):473-80. (Montez et al.)

Dietary Changes and Colorectal Cancer in Korea and Japan

Asian countries have been transitioning to a Westernized diet, which may be related to the increased incidence of colorectal cancer.  Korean researchers evaluated data regarding meat and cereal consumption in Korea and Japan, along with the incidence of colorectal cancer in those countries.  The transition in Korea is about 20 years behind Japan, but reflects a similar pattern of increased cancer with increased meat consumption and decreased cereal consumption.
Journal of Gastroenterology and Hepatology. 2008 Jan; 23(1):138-140. (Lee et al.)

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