Research Updates on ANTIOXIDANTS TO OMEGA-3S
By the end of 2009, products with antioxidant claims on their labels grew by 29% over the previous year, according to the “Nielsenwire Healthy Eating Trends Report.” Food is the most valuable source of antioxidants, thanks to the synergistically dynamic and complementary action of various phytochemicals. Research continues into the effects and benefits from individually extracted phytonutrient substances, alone or in conjunction with other compounds.
Consumer belief in the additional healthful properties of blueberries, almonds, dark chocolate, pomegranate juice, walnuts, raspberries, ginger and cinnamon has increased significantly--by at least 10-20%--over the past four years, earning them designations such as “magic food,” or super stars, according to Decision Analyst’s “Health and Nutrition Strategist--Food Ingredient What’s Hot? Demystifying Ingredient Seeking Among American Consumers,” March 2010, analysis. The report cites scientific support and media coverage for influencing consumer opinions.
Berries, naturally rich in polyphenols, are a valuable resource for combating elevated blood sugar response, by influencing carbohydrate digestion and absorption. Meals and diets that cause highly elevated blood sugar response are associated with an increased risk for obesity, type 2 diabetes and heart disease. Study results published in the British Journal of Nutrition reveal improved post-meal blood sugar response in healthy individuals from a sugar-sweetened bilberry, blackcurrant, cranberry and strawberry purée, as compared to sucrose alone
The polyphenolic anthocyanins abundant in blueberries are associated with better brain and memory function. The results of a study of adults with early signs of memory changes conducted by the University of Cincinnati Academic Health Center Department of Psychiatry suggested supportive benefits from daily consumption of wild blueberry juice over a 12-week period. Similar findings from Concord grape juice show the potential to forestall progression of age-related memory decline
Diabetics tend to have less of a favorable high-density lipoprotein (HDL)-associated ratio than people without the condition. This increases their heart health risk, as compared to healthy control subjects, because diabetes is also associated with increased oxidative stress for antioxidants. Pomegranate juice polyphenols can help increase heart health protection for diabetics. Researchers at the Rambam Medical Center of the Rappaport Family Institute for Research in Medical Sciences and Technion Faculty of Medicine, in Haifa, Israel, found pomegranate juice polyphenols beneficially impacted HDL beyond their antioxidative effect
Just one small square of chocolate a day can lower blood pressure and reduce heart disease risk, report researchers at the German Institute of Human Nutrition in Nuthetal. The study, published in the European Heart Journal, followed 19,357 people between 35-65 years of age for at least 10 years. The results revealed that subjects who ate the most amount of chocolate--an average of 7.5g a day--had lower blood pressure and a 39% lower risk of having a heart attack or stroke, when compared to those who ate the least amount of chocolate, an average of 1.7g a day. The difference between the two groups amounted to 6g of chocolate, the equivalent of less than one small square of a 100g bar
Participants in the Potsdam arm of the European Prospective Investigation into Cancer who ate the most chocolate--around 7.5g a day--were at a 39% lower risk of cardiovascular disease than those with the lowest chocolate intake. Over an eight-year period, people in the top quarter of the sampling had a 27% reduced risk of heart attacks and nearly half the risk (48%) of strokes, compared to those in the lowest quarter. “Our hypothesis was that because chocolate appears to have a pronounced effect on blood pressure, therefore, chocolate consumption would lower the risk of strokes and heart attacks, with a stronger effect being seen for stroke,” explained research leader Brian Buijsse, Ph.D., a nutritional epidemiologist at the German Institute of Human Nutrition, Nuthetal, Germany. “To put it in terms of absolute risk, if people in the group eating the least amount of chocolate (of whom 219 per 10,000 had a heart attack or stroke) increased their chocolate intake by 6g a day, 85 fewer heart attacks and strokes per 10,000 people could be expected to occur over a period of about 10 years.”
“If the 39% lower risk is generalized to the general population, the number of avoidable heart attacks and strokes could be higher, because the absolute risk in the general population is higher,” said Buijsse. He warned, however, that people should be wary of eating chocolate, if it increased their overall intake of calories or reduced their consumption of healthy foods.
The flavanols in cocoa may account for the perceived benefit of chocolate consumption on blood pressure and heart health, and the greater flavanol content in dark chocolate may provide even greater effects. Commenting on the research on behalf of the European Society of Cardiology (ESC), Frank Ruschitzka, professor of cardiology, director of Heart Failure/Transplantation at the University Hospital Zurich, Switzerland, and a fellow of the ESC, said, “Basic science has demonstrated quite convincingly that dark chocolate, particularly with a cocoa content of at least 70%, reduces oxidative stress and improves vascular and platelet function.”
Spicing It Up to Omegas
Dried herbs and spices can be a rich source of antioxidants. University of California researchers recently published findings that suggest adding antioxidant-rich spice to hamburger meat results in a 71% reduction of carcinogen and blood vessel plaque-promoting compounds, as compared to burgers prepared without the spice
In its Oxygen Radical and Absorbance Capacity (ORAC) rankings, the USDA ranked its top 20 foods for antioxidant capacities differently, based upon a 100g standard vs. a typical serving size, to illustrate the importance of serving size when assessing intake. Spices and chocolates dominated the per 100g list; fruits, berries and various apple varieties dominated the per typical serving size list. Although spices, cinnamon and cloves were included in the household measure list, one teaspoon of those spices is considered a “generous” amount that may not typically be used in one serving.
Data from 1,436 participants in the Diabetes Control and Complications Trial from the MRC Epidemiology Unit, Institute of Metabolic Science, Cambridge, UK, reveals dietary intake of omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) could be protective for kidney health among those with diabetes, a condition that increases risk for kidney disease. An inverse association was observed with the severity of urinary protein, an indicator of kidney health, in type 1 diabetes. Kidney function was improved with the highest average intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to people with the lower intakes of the fatty acids, as reported from findings published in Diabetes Care
The FDA has provided for heath claims and qualified health claims for certain foods and food components. The long road towards achieving those desirable claims is paved with solid scientific research. NS
SIDEBAR: Toasting Tea
Research into green tea’s health benefits continues at a brisk pace. Papers strive to detail the biological mechanisms behind the benefit of tea and its components. For example, one study discussed the potential cancer prevention effects of tea’s powerful antioxidant component epigallocatechin-3-gallate (EGCG). (Dou, QP. 2009. Nutr Cancer. 61:827-35.) Another paper reviewed epidemiological evidence from randomized controlled trials on green tea or green tea extracts and reduced cardiovascular risk and noted that over half the studies demonstrated a beneficial effect. The author said the results suggest a plausible mechanism for green tea’s benefits. (Kuriyama, S. 2008. J Nutr. 138:1548S-1553S.) A paper published online, April 2010, used a lower life form--worms--to elucidate the mechanism behind EGCG’s apparent ability to protect against ROS-mediated and age-related diseases. (Abbas, S. and Wink, M. 2010. Epigallocatechin gallate inhibits beta amyloid oligomerization in Caenorhabditis elegans and affects the daf-2/insulin-like signaling pathway. Phytomedicine. [Epub ahead of print.]) No doubt, much more is to come.
--Claudia D. O’Donnell, Chief Editor
SIDEBAR: Processing and Analyzing Soy
While clinical research works to link antioxidant-containing dietary components and health benefits, understanding the antioxidant contribution levels of foods and ingredients is challenging. For example, one study looked at several solvents (including a “gastrointestinal mimic”) used in extraction of a whole soy powder, soy concentrate and isolate, and isoflavone concentrate, and the impact of these factors on antioxidant compounds and units of measurements. These included total phenols, quinone reductase, antioxidant scavenging of four compounds and antioxidant capacity using FRAP and ORAC assays. The conclusion was that “…extraction methods markedly affect the antioxidant profile and QR induction capacity of soy products.” (Bolling, BW, et al. 2009. Extraction methods on antioxidant levels of soy products determine the antioxidant capacity and induction of quinone reductase by soy products in vitro. Food Chem. 116:351-355.)
--Claudia D. O’Donnell, Chief Editor