Scientific Update
Organic Foods: Better? Safer?
A limited number of research studies examines the nutritional quality of organic foods. The French Agency for Food Safety convened a group of 50 experts who spent more than two years examining all published research on organic foods. 1 Updated results of their review were recently released and include the following:
- Higher levels of iron and magnesium in organic vegetables than in conventional vegetables
- Higher levels of antioxidants in organic fruits and vegetables than in conventional fruits and vegetables
- Pesticide residues, as expected, markedly lower than in conventionally produced foods. Most often, pesticide residues in organic foods were non-existent.
- Lower levels of nitrates in organic vegetables
- Similar levels of most minerals and beta-carotene in organic and conventional foods.
These results show that organic products offer some significant advantages over conventionally grown products in terms of nutritional content and lower levels of pesticides and other potentially harmful substances.
Interestingly, another recent review of scientific research did not find any significant difference in nutritional quality between organic and conventional food. 2 This survey did not look at pesticide levels.
1 Lairon D. 2009. Nutritional quality and safety of organic food: A review. Agron Sustain Dev.
2 Danhour AD, Dodhia SK, Hayter A, et al. 2009. Nutritional quality of organic foods: a systematic review. Am J Clin Nutr 90:680-85.
Make No Bones About It
Osteoporosis-the result of years of bone density loss-can lead to broken bones, reduced mobility, and other unpleasant consequences. Good nutrition seems to be important for strong bones. A measurement called bone mineral density (BMD for short) is used to determine bone strength and to predict the likelihood of a person developing osteoporosis. There have been a number of studies of vegetarians, especially women, to see if a vegetarian diet affects BMD. These studies have often been small, and the results were not consistent. Researchers from Vietnam and Australia used a powerful tool called meta-analysis to combine results of nine studies of BMD in vegetarians. Six of the studies were of lacto-ovo vegetarians and three were of vegans. When the studies were combined, vegetarians had a 4 percent lower BMD than non-vegetarians. However-and this is an important however-the magnitude of the difference between vegetarians and non-vegetarians was not clinically significant. This means that the difference is very modest and would not be expected to significantly increase vegetarians' risk of osteoporosis or bone fracture. Vegans had a lower BMD than did lacto-ovo vegetarians. The study authors predict that vegans would have a slightly (perhaps 10 percent) higher risk of bone fracture compared to non-vegetarians. Neither dietary calcium nor protein intake could explain the difference in BMD between vegetarians or vegans and non-vegetarians. Other factors-such as weight-bearing exercise, vitamin D, vitamin K, and potassium-that play a role in bone health were not examined. From a practical standpoint, getting enough of key nutrients and regularly walking, running, or doing other weight-bearing exercise is your best bet for avoiding osteoporosis.
Ho-Pham LT, Nguyen ND, Nguyen TV. 2009. Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis. Am J Clin Nutr 90:1-8.
Vegetarian Diets Help Reduce Cholesterol
Close to half of adults in the United States have cholesterol levels that are higher than recommended. As a group, vegetarians tend to have lower blood cholesterol levels than non-vegetarians, and vegans have lower blood cholesterol than lacto-ovo vegetarians. Investigators recently looked at a number of studies that used vegetarian diets as a treatment for high cholesterol levels. They found that changing from a standard American diet to either a more plant-based diet (not vegetarian but limited meat) or a lacto-ovo vegetarian diet led to, on average, a 10 to 15 percent decrease in both cholesterol and LDL (bad) cholesterol levels. Changing to a vegan diet led to a 15 to 25 percent decrease in total cholesterol and LDL cholesterol. If a change was made to a vegetarian or vegan diet along with eating more fiber, soy, or nuts, a 20 to 35 percent decrease in cholesterol and LDL cholesterol levels was seen. In contrast, conventional dietary therapy for high cholesterol levels (non-vegetarian diet with lower saturated fat and cholesterol) only reduced total cholesterol and LDL cholesterol levels by 5 to 10 percent. The bottom line: Be good to your heart—go vegetarian. For more about heart-healthy vegetarian diets, see VRG's brochure at www.vrg.org/nutshell/hearthealth2.pdf and www.vrg.org/nutshell/hearthealth1.pdf.
Ferdowsian HR, Barnard ND. 2009. Effects of plant-based diets on plasma lipids. Am J Cardiol 104: 947-56.
AHA Urges Americans to Use Less Sugar and Sugary Foods
Did you know that the average American eats more than 22 teaspoonfuls of sugar a day? We don't just add sugar to cereal or coffee-it's added for us by food processors. Soft drinks account for approximately a third of the sugar Americans consume, while desserts and candy supply another third.
Over the past 30 years, the average calorie intake of Americans has increased by 150 to 300 calories per day. Approximately half of the increased calories comes from sugar-sweetened drinks. These higher calorie levels wouldn't be so bad if we were exercising more, but there was no change in activity over the period studied. That's one reason why obesity is increasing at a rapid rate.
Besides raising the risk for obesity and related health problems like diabetes, excess sugar intakes can lead to increased blood pressure and higher triglyceride levels. These health-related effects have prompted the American Heart Association to recommend that women get no more than 100 calories a day from added sugar and that most men stay under 150 calories per day from sugar. To put this in perspective, a typical can of soda provides 130 calories from added sugar.
Johnson RK, Appel LJ, Brands M, et al. 2009. Dietary sugars intake and cardiovascular health: a scientific statement from the American Heart Association. Circulation 120:1011-20.
Increased Rate of Type 2 Diabetes Forecast
Type 2 diabetes is the most common form of diabetes. It occurs more commonly in adults, although cases are being reported in children and adolescents as well. One risk factor for this disease is being overweight. As the population's weight increases, an increase in type 2 diabetes would be expected. Several researchers created a mathematical model to predict the development of type 2 diabetes over the next 25 years. Their model forecasts that the number of people with type 2 diabetes will increase from 23.7 million to 44.1 million by 2034. This increase will come with a price tag. By 2034, diabetes-related expenses are expected to triple to $336 billion yearly. Vegetarians have a lower risk of type 2 diabetes (www.vrg.org/journal/vj2009issue4/2009_issue4_scientific_update.php), and vegetarian diets have been shown to be an effective treatment for type 2 diabetes (www.vrg.org/journal/vj2007issue1/vj2007issue1.pdf).
Huang ES, Basu A, O'Grady M, et al. 2009. Projecting the future diabetes population size and related costs for the U.S. Diabetes Care 32:2225-29.
Type 2 Diabetes and Fish
Researchers from the Netherlands wondered if people who eat fish have a lower risk of developing type 2 diabetes. They studied close to 4,500 Dutch men and women, age 55 and older, who did not have diabetes at the start of the study. Subjects were asked how often they ate certain foods, including fish. The subjects were then followed for approximately 12 years to see which ones developed type 2 diabetes. Those subjects who ate the most fish had a 30 percent higher risk of developing type 2 diabetes, compared to those who never ate fish. Lean fish intake increased risk more than fatty fish and shellfish, which had no effect on risk. Intake of EPA and DHA (omega-3 fats found in fish) did not affect risk of type 2 diabetes. Eating fish does not appear to be protective against type 2 diabetes. Indeed, both vegans and lacto-ovo vegetarians have been shown to have a lower risk of type 2 diabetes than fish-eaters (www.vrg.org/journal/vj2009issue4/2009_issue4_scientific_update.php).
van Woudenburgh GJ, van Ballegooijen AJ, Kuijsten A, et al. 2009. Eating fish and risk of type 2 diabetes. Diabetes Care 32:2021-26.
