**Post written by guest writer Anh Thu Tran, MS, MD, a Nutrition Consultant**

Deliciously balanced with tartness and sweetness, often served chilled in a glass, and appearing on ~70% of American’s breakfast tables every morning is the ever-so-popular: OJ, otherwise known as orange juice.  This simple and nutritious way to start the day was introduced in the 1500s when early Spanish explorers planted the first orange tree around St. Augustine, which progressed to the first orange grove in 1830.

Today’s citrus craze continues to exist for its role in providing a delicious, excellent, and convenient way to meet the daily recommendations for fruits and vegetables.  Eight-ounces of orange juice provides a rich and natural source of Vitamin C, thiamin, folate, potassium, and other important nutrients found in the  equivalence of 3-4 medium whole oranges.

Antioxidants are vital for the defense system and proper functioning of the cells that make up our body.  The abundance of studies of such agents has contributed to the understanding of the mechanism behind a variety of health conditions and its potential role against them.  Free radicals are known to induce inflammation in blood vessel lining (e.g. dyslipidemia, hypertension, etc.) and compromise cell-to-cell interface (e.g. insulin-resistant diabetes mellitus).  Not only do we naturally form our own antioxidants in the body (known as endogenous antioxidants), with growing knowledge of its potential health benefits and consistent findings that our biological system as we age is overwhelmed by free radicals, single supplements and functional foods/beverages have also become a rich source (known as exogenous antioxidants).

The mere action of calorie intake, unfortunately that of more common nature as a high fat, high carbohydrate (HFHC) meal, is suggested to promote a cascade response in the body to form free radicals that subsequently activates pro-inflammatory agents contributing to many of the health concerns of today.

A recent study, published in the American Journal of Clinical Nutrition by Dr. Husam Ghanim from the State University of New York at Buffalo (NIH and ADA grant study), demonstrated drinking orange juice halts overwhelming effects of free radical cascade and offer insight explaining the natural goodness of orange juice.  Subjects consumed a HFHC meal at 900kcal with either water or 300kcal glucose or orange juice.  Pro-inflammatory effects were seen in HCHF meals consumed with either water or 300kcal glucose, but not with those subjects that drank orange juice.

It is a known fact that orange juice provides an excellent source of Vitamin C, but its antioxidant potential is beyond the activity of Vitamin C alone.  Orange juice has an ORAC value of ~726μmoles of Trolox equivalence per 100g.  This study narrowed the mechanism to these finding to 3 culprits: Vitamin C, fructose, and flavonoids (specifically Hesperetin and Naringenin).  Further investigation showed that vitamin C and fructose alone in orange juice were unable to suppress free radical production, but rather it was the antioxidant powers of flavonoids that combated successfully against the effects of oxidative stress and inflammation.  These findings are consistent to the protective effects of Hesperetin and Naringenin to cardiovascular and/or neurological diseases demonstrated in previous studies.

The daily value intake for antioxidants is suggested at an ORAC valued at 4000μmolesTE/100g with an emphasis coming from variety of sources foods/beverages.  In no means are these findings an avocation for consuming a cheeseburger and fries with orange juice.  Rather, the next time you reach for that crisp glass of OJ – realize it is no longer sole for the natural goodness of Vitamin C, but also Flavonoids – a more powerful source of antioxidants!

References

Ghanim H, Abuaysheth A, Sia CL et al., “Increase in plasma endotoxin concentrations and the expression of Toll-like receptors and suppressor of cytokine signaling in mononuclear cells after a high fat, high carbohydrate meal,” Diabetes Care (2009), 32:2281-2287.

Ghanim H, Sia CL, Upadhyay M et al., “Orange juice neutralize the proinflammatory effect of a high-fat, high-carbohydrate meal and prevents endotoxin increase and Toll-like receptor expression, “  Am J Clin Nutr (2010), 91: 940-949.

“Oxygen radical absorbance capacity (ORAC) of selected foods,” Nutrient Data Laboratory, Agriculture Research Services, U.S. Department of Agriculture (2007).

Author’s bio: Dr. Anh Thu Tran is the Nutrition Consultant and Research & Development Coordinator at Cyvex Nutrition.  She holds a M.D. from St. George’s University, a M.S. in Nutrition from Loma Linda University, a B.Sc. in Biology & Women’s Studies from UC Irvine, and will work under the UC Davis Family Residency Network 2010.

**Post written by guest writer Anh Thu Tran, MS, MD, a Nutrition Consultant**                                     See Anh Thu’s bio at the end of the post

In the natural progression of the biological system, overwhelming oxidation contributes to the theories of the aging process.  The body is constantly barraged with pollutants that are present inside and outside the body that cause free radical invasion which are highly and readily reactive.  Free radicals has the potential to create chemical reaction cascades that compromise the integrity of cells and their components vital  to proper functioning (including DNA) and drain the body’s natural antioxidant enzymes.  The subsequent damaging effects can be explained when accumulation of free radicals off-balances the body’s natural defense system, which increases susceptibilities to a number of chronic conditions.  It is no wonder in the interest and abundance of continuous studies in the context of this mechanism and potential agents to modulate their detrimental effects.

However, in order to understand the need, the status of deficit (if any) should be addressed.  Based on the NHANES crosslink of the USDA flavonoid database, food consumption data, and dietary supplements data of the approximately 9000 adults (≥ 19 years old) in a free-living population in the U.S., only 210mg of flavonoids are consumed daily.  Ninety-eight percent were from the diet alone and only 4% from supplements.  The greatest sources of flavonoids intake of these adults are as followed: tea (157mg), citrus fruit juices (8mg), wine (4mg), and citrus fruits (3mg).  The estimated mean of daily total breakdown of flavonoids was ~84% of flavan-3-ols, followed by ~8% flavanones (e.g. Fisetin), ~7% of flavonols, ~2% of anthocyanidins, ~1% of flavones (e.g. Apigenin, Diosmin, Luteolin, Nobiletin, Tangeretin), and ~1%of isoflavones.  Although the intake is the highest among all the antioxidant sources assessed (compared to vitamin A, C, and E, and selenium), beneficial efficacy of flavonoids as a whole and individually has been demonstrated at higher levels of intake.  The human equivalence dose (HED) of Fisetin alone is approximately 50 – 125mg/day to obtain the neuroprotective effects, which means one would have to consume 10-30 apples, 200-400 onions, or 300-500 strawberries a day.

Indeed the consumption of a well-balanced diet is the best way to boost your natural defenses, but these findings indicate how difficult it is to meet the beneficial levels of antioxidants solely from flavonoids naturally found in foods and beverages.   With increasing findings of advantageous antioxidant, anti-inflammatory, neuroprotection and other effects of the flavonoids, the intake of supplementation of a single dietary flavonoid or as part of a flavonoid-rich preparation in a functional food/beverage present great potential in the promotion of optimal nutrition and healthy aging.

References

Arai Y et al.  “Dietary intakes of flavonol, flavones and Isoflavones by Japanese women and the inverse correlation between Quercetin intake and plasma LDL cholesterol concentration.”  Am Soc Nutr Sciences (2000).

Chun OK et al., “Estimated dietary flavonoid intake and major food sources of U.S. adults,” J Nutr (2007).

Chun OK et al., “Estimation of antioxidant intakes from diet and supplements in U.S. adults,” J Nutr (2010).

Maher P.  “Modulation of multiple pathways involved in the maintenance of neuronal function during aging by fisetin,” Genes Nutr (2009).

Author’s bio:

Dr. Anh Thu V. Tran is the Nutrition Consultant and Research & Development Coordinator at Cyvex Nutrition.  She is driven by her ambitions to intertwine the needs and trends of consumers by providing a practical, yet scientific approach.  She previously worked as a Junior Project Manager and Research Nutritionist at Profil Institute for Clinical Research for metabolic diseases and as a dietary and preventive health counselor for the Center for Health Promotion, Loma Linda University and the Prevention and Control Program – Cancer Center, UC San Diego.  She holds a Doctor of Medicine from St. George’s University, a Masters in Nutritional Sciences from Loma Linda University, a Bachelor of Science in Biological Sciences and Women’s Studies from UC Irvine, and will begin her Family Medicine Residency at San Joaquin General Hospital – UC Davis summer 2010.  She is actively involved with non-profit organizations:  Project Viet Nam Foundation (PVNF), Vietnamese Children Asthma Project (VCAP), and SACHS Norton Clinic – LLU.  She is an advocate of an active and balanced lifestyle through healthy eating, Pilates, and running.  Her approach deters one from finding “the magic bullet” to solve all, but rather encompass a multimodal distribution in improving the quality of life.