Group items tagged

Current impediments to acceptance of the ultraviolet-B-vitamin D-cancer hypothesis. Grant WB, Boucher BJ. Anticancer Res. 2009 Sep;29(9):3597-604. PMID: 19667154 The ultraviolet-B (UVB)-vitamin D-cancer hypothesis was proposed in 1980. There have been numerous ecological, observational and other studies of the hypothesis. There are about 14 types of cancer for which it seems to apply: bladder, breast, colon, endometrial, esophageal, gallbladder, gastric, ovarian, pancreatic, rectal, renal and vulvar cancer and both Hodgkin's and non-Hodgkin's lymphoma. Nonetheless, the hypothesis has not yet been accepted by public health agencies. Some of the reasons for this include a distrust of ecological studies, some mistrust of observational studies, and the existence of just one positive randomized controlled trial, an analysis of a vitamin D and calcium supplementation study involving post-menopausal women in Nebraska. Paradigm shifts such as this generally take time, in part due to opposition from those content with the status quo. In this paper, results of ecological studies in the United States using summertime solar UVB as the index of vitamin D production, which is highly asymmetrical with respect to latitude, and indices for other cancer risk-modifying factors (air pollution, alcohol consumption, dietary iron and zinc, ethnic background, socioeconomic status, smoking and urban/rural residence) are discussed in terms of supporting the hypothesis. These studies were not considered while other ecological studies were examined in recent critiques of the hypothesis. While additional randomized controlled trials would, of course, be helpful, the current evidence seems to satisfy the criteria for causality as outlined by A. Bradford Hill.

Not enough vitamin D: health consequences for Canadians. Schwalfenberg G. Can Fam Physician. 2007 May;53(5):841-54. Review PMID: 17872747 Conclusion Low levels of VTD are considered a major public health problem in Canada, especially during the winter. Those with risk factors should be screened for low 25(OH)D levels and repletion therapy instituted if needed. Researchers have estimated that the oral dose of vitamin D3 to attain and maintain 25(OH)D levels >80 nmol/L is 2200 IU/d if baseline levels are 20 to 40 nmol/L, 1800 IU/d if levels are 40 to 60 nmol/L, and 1160 IU/d if levels are between 60 and 80 nmol/L.64 We need to ensure that patients have healthy blood levels of 25(OH)D to prevent levels of parathyroid hormone from rising and to maximize absorption of calcium, magnesium, and phosphate. Positive effects on bone are marginal at best unless patients consume at least 800 IU/d of VTD. The emerging and exciting role of the VTD receptor and the actions of VTD in maintaining health in other cell types have become more apparent during the last decade.

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.

"Researchers at Johns Hopkins are reporting what is believed to be the first conclusive evidence in men that the long-term ill effects of vitamin D deficiency are amplified by lower levels of the key sex hormone estrogen, but not testosterone. In a national study in 1010 men, to be presented Nov. 15 at the American Heart Association's (AHA) annual Scientific Sessions in Orlando, researchers say the new findings build on previous studies showing that deficiencies in vitamin D and low levels of estrogen, found naturally in differing amounts in men and women, were independent risk factors for hardened and narrowed arteries and weakened bones. Vitamin D is an essential part to keeping the body healthy, and can be obtained from fortified foods, such as milk and cereals, and by exposure to sunlight.

The results suggest that a short-term ketogenic diet does not have a deleterious effect on CVD risk profile and may improve the lipid disorders characteristic of atherogenic dyslipidemia. A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. Sharman MJ, Kraemer WJ, Love DM, Avery NG, Gómez AL, Scheett TP, Volek JS. J Nutr. 2002 Jul;132(7):1879-85. PMID: 12097663

Prevalence and Associations of 25-Hydroxyvitamin D Deficiency in US Children: NHANES 2001-2004. Kumar J, Muntner P, Kaskel FJ, Hailpern SM, Melamed ML. Pediatrics. 2009 Aug 3. [Epub ahead of print] PMID: 19661054 CONCLUSIONS: 25(OH)D deficiency is common in the general US pediatric population and is associated with adverse cardiovascular risks.

Vitamin D's days of obscurity seem pretty much over. Once just an afterthought to most people-relegated to the sides of milk cartons and the pages of medical texts-it's now on the cusp of becoming a full-fledged disease prevention star. Although vitamin D has long been known as an important factor in bone health, a quickly growing body of evidence now shows that it may also help lower the risk of cancer, heart disease, and even premature death.[1], [2] Not surprisingly, scientists and the public have started to take note, particularly of vitamin D's potential to protect against cancer

Vitamin K has been known as the coagulation vitamin, because of its role in the blood-clotting process. However, research over the last few decades has shown that the role of K Vitamins - and natural Vitamin K2, the menaquinones, in particular - has been greatly expanded. Of note, K Vitamins activity outside the liver is required for calcium utilization, the key factor in maintaining both bone and cardiovascular health.\n\nVitamin K2 helps to activate vitamin K-dependent proteins responsible for healthy tissues. In bone, it activates osteocalcin, a protein required to bind calcium to the mineral matrix, thus strengthening the skeleton. In circulation, Vitamin K2 participates in carboxylation of Matrix Gla Protein (MGP), the most potent inhibitor of arterial calcification known, lowering the risk of vascular damage.

Blood pressure and atherogenic lipoprotein profiles of fish-diet and vegetarian villagers in Tanzania: the Lugalawa study. Pauletto P, Puato M, Caroli MG, Casiglia E, Munhambo AE, Cazzolato G, Bittolo Bon G, Angeli MT, Galli C, Pessina AC. Lancet. 1996 Sep 21;348(9030):784-8. PMID: 8813985 Interpretation In these villagers, consumption of freshwater fish (300-600 g daily) was associated with raised plasma concentrations of n-3 polyunsaturated fatty acids, lower blood pressure, and lower plasma lipid concentrations. In conclusion, our findings confirm that the favourable risk factor profile originally described for Eskimos living on a diet rich in n-3 polyunsaturated fatty acids is real, and not overestimated.

Effect of vitamin D deficiency and replacement on endothelial function in asymptomatic subjects. Tarcin O, Yavuz DG, Ozben B, Telli A, Velioglu Ogunc A, Yuksel M, Toprak A, Yazici D, Sancak S, Deyneli O, Akalin S. J Clin Endocrinol Metab. 2009 Jul 7. [Epub ahead of print] PMID: 19584181 doi:10.1210/jc.2008-1212 Conclusions: This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D associated endothelial dysfunction may predispose to higher cardiovascular disease in the winter.

Hypovitaminosis D in medical inpatients. Thomas MK, Lloyd-Jones DM, Thadhani RI, Shaw AC, Deraska DJ, Kitch BT, Vamvakas EC, Dick IM, Prince RL, Finkelstein JS. N Engl J Med. 1998 Mar 19;338(12):777-83. PMID: 9504937 Conclusions Hypovitaminosis D is common in general medical inpatients, including those with vitamin D intakes exceeding the recommended daily amount and those without apparent risk factors for vitamin D deficiency.

Serum 25-hydroxyvitamin D3 concentrations and carotid artery intima-media thickness among type 2 diabetic patients. Targher G, Bertolini L, Padovani R, Zenari L, Scala L, Cigolini M, Arcaro G. Clin Endocrinol (Oxf). 2006 Nov;65(5):593-7. PMID: 17054459 DOI: 10.1111/j.1365-2265.2006.02633.x CONCLUSIONS: Hypovitaminosis D is highly prevalent in type 2 diabetic adults and is strongly and independently associated with increased carotid IMT. Further investigation into whether vitamin D may play a role in the prevention of atherosclerosis appears to be warranted. In conclusion, our results show that type 2 diabetic adults have significant reductions in serum 25(OH)D concentrations (vs matched controls) that predict preclinical atherosclerosis, independent of classical risk factors, renal function tests, inflammatory markers, use of medications and presence of the metabolic syndrome. These findings suggest the need for ongoing evaluation of the possible protective role of vitamin D3 supplementation in the development of atherosclerosis.

Effects of a Mediterranean-style diet on the need for antihyperglycemic drug therapy in patients with newly diagnosed type 2 diabetes: a randomized trial. Esposito K, Maiorino MI, Ciotola M, Di Palo C, Scognamiglio P, Gicchino M, Petrizzo M, Saccomanno F, Beneduce F, Ceriello A, Giugliano D. Ann Intern Med. 2009 Sep 1;151(5):306-14. PMID: 19721018 Conclusion: Compared with a low-fat diet, a low-carbohydrate, Mediterranean-style diet led to more favorable changes in glycemic control and coronary risk factors and delayed the need for antihyperglycemic drug therapy in overweight patients with newly diagnosed type 2 diabetes.

Geographic variation in breast cancer mortality in the United States: a hypothesis involving exposure to solar radiation. Garland FC, Garland CF, Gorham ED, Young JF. Prev Med. 1990 Nov;19(6):614-22. PMID: 2263572 doi:10.1016/0091-7435(90)90058-R Vitamin D from sunlight exposure may be associated with low risk for fatal breast cancer, and differences in ultraviolet light reaching the United States population may account for the striking regional differences in breast cancer mortality. The ecological nature of this study is emphasized, and the possibility that an indirect association with dietary and socioeconomic factors could explain these findings is discussed.

Higher levels of 25-hydroxyvitamin D are associated with a lower incidence of multiple sclerosis only in women. Kragt J, van Amerongen B, Killestein J, Dijkstra C, Uitdehaag B, Polman Ch, Lips P. Mult Scler. 2009 Jan;15(1):9-15. Epub 2008 Aug 13. PMID: 18701572 DOI: 10.1177/1352458508095920 CONCLUSIONS: Our data suggest that higher circulating levels of 25(OH)D are associated with a lower incidence of MS and MS-related disability in women. This may imply clues to the pathogenesis of the sex difference in risk and to the nature of the environmental factors involved in MS.

Conclusion A low-carbohydrate plant-based diet has lipid-lowering advantages over a high-carbohydrate, low-fat weight-loss diet in improving heart disease risk factors not seen with conventional low-fat diets with animal products. The Effect of a Plant-Based Low-Carbohydrate ("Eco-Atkins") Diet on Body Weight and Blood Lipid Concentrations in Hyperlipidemic Subjects David J. A. Jenkins; Julia M. W. Wong; Cyril W. C. Kendall; Amin Esfahani; Vivian W. Y. Ng; Tracy C. K. Leong; Dorothea A. Faulkner; Ed Vidgen; Kathryn A. Greaves; Gregory Paul; William Singer Arch Intern Med. 2009;169(11):1046-1054. DOI: 10.1001/archinternmed.2009.115

Association of low intake of milk and vitamin D during pregnancy with decreased birth weight. Mannion CA, Gray-Donald K, Koski KG. CMAJ. 2006 Apr 25;174(9):1273-7. PMID: 16636326 doi:10.1503/cmaj.1041388. Interpretation: Milk and vitamin D intakes during pregnancy are each associated with infant birth weight, independently of other risk factors.

Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet. Mutungi G, Ratliff J, Puglisi M, Torres-Gonzalez M, Vaishnav U, Leite JO, Quann E, Volek JS, Fernandez ML. J Nutr. 2008 Feb;138(2):272-6. PMID: 18203890 Carbohydrate-restricted diets (CRD) significantly decrease body weight and independently improve plasma triglycerides (TG) and HDL cholesterol (HDL-C) . [..] Eighteen subjects were classified as having the metabolic syndrome (MetS) at the beginning of the study, whereas 3 subjects had that classification at the end. These results suggest that including eggs in a CRD results in increased HDL-C while decreasing the risk factors associated with MetS.