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According to a study conducted by University of Wisconsin researchers, even people who are regularly exposed to sunlight can have low vitamin D levels.\n\nThe study focused on subjects who lived in sunny Hawaii and spent an average of 11.1 hours in the sun each week. (None of the participants in the study used any type of sunscreen.) Despite the exposure, 51 percent of participants were found to be deficient in vitamin D.

Circulating vitamin D3 and 25-hydroxyvitamin D in humans: An important tool to define adequate nutritional vitamin D status. Hollis BW, Wagner CL, Drezner MK, Binkley NC. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):631-4. Epub 2007 Jan 10. PMID: 17218096 In the present study, we sought to investigate what circulating 25(OH)D levels would result in populations exhibiting no substrate limitations to the vitamin D-25-hydroxylase. To perform this, we chose two distinct populations. The first were individuals from a year-found sunny environment who spent a good deal of time outdoors. The second were a group of lactating women receiving a substantial daily oral dose of vitamin D3. Surprisingly, a study such as this previously had not been undertaken. There are several reasons for this. First, finding a group of sun-exposed individuals is not an easy task; in fact, we had to go to Hawaii to find them. Secondly, very few studies have been performed where subjects actually received adequate vitamin D3 supplementation to make them replete. Finally, it is very difficult and costly to measure circulating vitamin D3 and relate it to circulating 25(OH)D. The results of our study are far-reaching. This study also demonstrates that individuals can be vitamin D deficient with significant sun exposure if the skin area exposed is limited as was suggested several years ago (19). Finally, whether one receives their vitamin D3 orally or through UV exposure, the vitamin D-25-hydroxylase appears to handle it in an equivalent fashion with respect to maintaining circulating 25(OH)D levels. Thus, we believe that the relationship between circulating vitamin D and 25(OH)D may define adequate nutritional vitamin D status.

"It's well known that African Americans have low levels of vitamin D in their blood. In fact, this seems to be generally true for humans of tropical origin. In a study from Hawaii, vitamin D status was assessed in healthy, visibly tanned young adults who averaged 22.4 hours per week of unprotected sun exposure. Yet 51% had levels below the current recommended minimum of 75 nmol/L (Binkley et al., 2007). In a study from south India, levels below 50 nmol/L were found in 44% of the men and 70% of the women. The subjects are described as "agricultural workers starting their day at 0800 and working outdoors until 1700 with their face, chest, back, legs, arms, and forearms exposed to sunlight" (Harinarayan et al., 2007). In a study from Saudi Arabia, levels below 25 nmol/L were found in respectively 35%, 45%, 53%, and 50% of normal male university students of Saudi, Jordanian, Egyptian, and other origins (Sedrani, 1984)."

"Study Shows Baked Fish Is Better for Heart Health Than Fried, Salted, or Dried Nov. 19, 2009 (Orlando, Fla.) -- When it comes to reaping the heart-healthy benefits of omega-3 fatty acids in fish, it often comes down to how you prepare it, a study shows. "The take-home message is that it's better to bake or boil the fish instead of frying it," says study researcher Lixin Meng, MS, a doctoral candidate at the University of Hawaii at Manoa. And adding a dash of low-sodium soy sauce will enhance the heart-healthy benefits, she tells WebMD. Eating salted, dried, or fried fish, on the other hand, is not beneficial, Meng says. "But if it's a fun occasion and you really want fried fish, do it the Japanese way -- stir-fry, rather than deep-fry it.""

"The results of the uniquely-constructed ERA JUMP Study were just released, a fascinating study of the relationship of omega-3 fatty acids to coronary and carotid plaque. The study adds insight into why the Japanese experience only one third of the heart attacks of Americans, and why Japan occupies the bottom of the list for least heart attacks among all developed countries. The Electron-Beam Tomography, Risk Factor Assessment Among Japanese and U.S. Men in the Post-World War II Birth Cohort Study (ERA JUMP), a collaborative U.S.-Japanese effort, compared three groups of men: -- 281 Japanese men living in Japan -- 306 non-Japanese men living in the U.S. (Pittsburgh, Pennsylvania) -- 303 Japanese Americans (having both parents Japanese without "ethnic admixture") living in Hawaii. The last group represents a group that is genetically similar to the group in Japan, but exposed to an American diet and lifestyle. Three main measures were compared: -- Blood levels of omega-3 fatty acids, EPA and DHA) -- Carotid intimal-medial thickness (CIMT, the thickness of the carotid artery lining that can serve as an index of body-wide atherosclerosis) -- Coronary calcium (heart scan) scores."

July 29, 2008 - The low rate of atherosclerosis and heart disease in Japanese people may be related to their very high levels of marine-derived omega-3 fatty acids rather than genetic factors, a new study suggests [1]. The study, known as Electron-Beam Tomography, Risk Factor Assessment Among Japanese and US Men in the Post-World War II Birth Cohort (ERA JUMP) included 868 randomly selected men aged 40 to 49. Of these, 281 were Japanese men living in Japan; 306 were white men living in the US, and 281 were third- or fourth-generation Japanese American men from Hawaii. All study participants had a physical examination, completed a lifestyle questionnaire, and had blood tests to measure cholesterol levels and levels of omega-3 fatty acids. Atherosclerosis was assessed by measuring carotid intima-medial thickness (IMT) and coronary artery calcification (CAC). Results showed that the Japanese men had the lowest levels of atherosclerosis, whereas whites and Japanese Americans had similar higher levels. The Japanese men also had twofold higher levels of marine-derived omega-3 fatty acids than white and Japanese Americans. The study, published in the August 5, 2008 issue of the Journal of the American College of Cardiology (available online July 28), was conducted by a group led by Dr Akira Sekikawa (University of Pittsburgh, PA, and Shiga University of Medical Science, Japan). They found that compared with white or Japanese American men living in the US, Japanese men living in Japan had twice the blood levels of omega-3 fatty acids - a finding that was independently linked to low levels of atherosclerosis.

Tofu and cognitive function: food for thought. Grodstein F, Mayeux R, Stampfer MJ. J Am Coll Nutr. 2000 Apr;19(2):207-9. Review. PMID: 10763901 In addition, a plausible biologic hypothesis is generally an important part of judging epidemiologic relations. While high tofu intake may lead to lower plasma estrogen levels [12], we do not know how tofu influences estrogen levels in the brain; we also know very little about estrogen effects in men. Furthermore, data have not even consistently indicated that low endogenous estrogen levels are directly related to cognitive function in non-demented subjects [13]. The authors also posit a non-estrogen mediated hypothesis for the effects of tofu, namely that soy inhibits hippocampal tyrosine kinase and may block long-term potentiation (the likely mechanism by which humans learn and remember). Still, considerably more work must be done to substantiate this hypothesis. Finally, the single measures of outcome used in this study may have limited value, as cognitive function and brain structure change over time. Factors which predict these measures at one point may or may not be the same as those which predict decline over time; fundamentally, the public health interest is in preventing cognitive decline, as the steepness of the decline trajectory likely provides an early marker for risk of the more clinically relevant result-dementia.