New studies add life-saving luster to two vital foods
by Craig Weatherby
The good news about fish and berries just keeps on rolling in. If you already eat either or both on a regular basis, you’ll feel very good about these new findings. And if you don’t enjoy fish and berries often enough, think again—they may help your heart and your mood!
Fish oils ameliorate teen anger, and heart risks in adulthood
A study published earlier this month1 indicates that teens whose diets are high in fish or DHA—an omega-3 fatty acid found only in fish oils—enjoy lower hostility levels and a reduced risk of coronary artery disease. As the authors noted, "Hostility has been shown to predict both the development and manifestation of coronary disease."
The researchers analyzed the diets and behavior of about 3,600 city-dwelling adolescent boys and girls (white and black), and found that those who consumed higher levels of either DHA or whole fish rich in DHA displayed lower hostility rates than their fish-deprived peers. These results make sense in the light of abundant prior research2-8 showing that omega-3 fatty acids have beneficial effects on depression, anxiety, impulsiveness, and aggression.
Cold-water fish species offer the highest levels of omega-3s (DHA and EPA)—and wild salmon contains more of them than most.
Blueberries found helpful to arteries and heart health
It seems that the blueberry-loving bears of Maine and Alaska are onto something big. Last October, researchers reported evidence9 that wild blueberries can help reduce a key risk factor for cardiovascular disease.
The study showed that the arteries of lab rats fed a diet high in wild blueberries remain more relaxed in response to stress hormones, compared with rats on otherwise identical berry-free diets. The daily dose of blueberries given to the rats equates to about one and one-half cups of blueberries per day for humans.
As lead author Dorothy Klimis-Zacas, Ph.D., associate professor at the University of Maine said, "We know now that blueberries affect the contractile machinery of the artery." The positive impact of the blueberry-rich diet applied to older rats as well, implying that it is never too late to benefit from adding blueberries to ones diet.
While the researchers did not identify the nutritional factors that kept arteries more relaxed, they hypothesized that blueberries’ high concentrations of antioxidants and trace minerals (e.g., manganese) are likely responsible.
After performing experiments on the inner surface of the artery, the authors concluded that the blueberry-rich diets probably produced their benefit by preserving the bioavailability of nitric oxide—an antioxidant bodily chemical that helps to relax the arteries.
- Iribarren C, Markovitz JH, Jacobs DR, Schreiner PJ, Daviglus M, Hibbeln JR. Dietary intake of n-3, n-6 fatty acids and fish: Relationship with hostility in young adults-the CARDIA study. Eur J Clin Nutr. 2004 Jan; 58(1): 24-31.
- Virkkunen ME, Horroboin DF, Jenkins DK, Manku MS: Plasma phospholipid essential fatty acids and prostaglandins in alcoholic, habitually violent and impulsive offenders. Biol Psychiatry 1987; 22: 1087-1096.
- Hamazaki T, Sawazaki S, Itomura M, Asaoka E, Nagao Y, Nishimura N, Yazawa K, Kuwamori T, Kobayashi M: The effect of docosahexaenoic acid on aggression in young adults. A placebo-controlled double-blind study. J Clin Invest 1996; 97: 1129-1133.
- Weidner G, Connor SL, Hollis JF, Connor WE: Improvements in hostility and depression in relation to dietary change and cholesterol lowering. Ann Int Med 1992; 117: 820-823.
- Hibbeln JR, Linnoila M, Umhau JC, Rawlings R, George DT, Salem N Jr. Essential fatty acids predict metabolites of serotonin and dopamine in cerebrospinal fluid among healthy control subjects, and early- and late-onset alcoholics. Biol Psychiatry 1998; 44: 235-242.
- Hibbeln JR, Salem N Jr. Dietary polyunsaturated fatty acids and depression: when cholesterol does not satisfy. Am J Clinical Nutr 1995; 62: 1-9.
- Hibbeln JR, Salem N Jr. Risks of cholesterol-lowering therapies. Biological Psychiatry 1996; 40: 7: 686-687.
- Hibbeln JR, Umhau JC, George DT, Salem N Jr. Do Plasma Polyunsaturates predict Hostility and Violence? World Rev Nutr Diet 1996; 82: 175-186.
- Klimis-Zacas D, Norton C, Kalea A, et al. Wild Blueberries May Help to Protect Arteries, Reduce Risks from Cardiovascular Disease http://www.umaine.edu/News/111003/WildBlueberries.htm