Get In 2 Vitamin D

Here's a great article describing the association of low blood vitamin D levels and asthma in equatorial children. The study found a significant association between low vitamin D and asthma, as well as hospitalization for asthma, inflammatory markers and airway responsiveness. The limitations of the study are that it is just a description - there were no comparison children, and no "intervention" was done. One of the key things about this review, however, for everyone wondering WHY someone doesn't go ahead and study the problem more thoroughly (or treat these children with vitamin D!), is this edotorial explanation addressing just that issue: "In an accompanying editorial, Graham Devereux, MD, from the University of Aberdeen in Aberdeen, United Kingdom, and colleagues discuss the difficult scientific, ethical, and regulatory issues involved in intervention studies of vitamin D in the primary prevention and treatment of asthma." "'Studies that supplement with the currently recommended doses of vitamin D, while unlikely to raise ethical or regulatory concerns, would fail to address the scientific evidence that larger vitamin D intakes (e.g., 2,000 IU/d) may be required for beneficial nonskeletal effects,' the editorialists write. 'While these concerns may be satisfactorily addressed, it remains to be seen whether pregnant women, parents, or patients will be similarly convinced and participate in such studies. Ultimately, it is only by investigating the effects of vitamin D in doses at, and above those currently recommended, that decisions can be made on the optimal intake of vitamin D for health and the possible prevention and treatment of asthma.'" Interesting, huh?

Vitamin D has long been known as a crucial factor in muscle strength and tone. People who are vitamin D deficient have less muscle strength - and muscle weakness corrects quickly once you restore their vitamin D status to normal. Calcium is also a crucial factor in the onset of labor in pregnant women - and vitamin D levels are crucial for your calcium balance. How do these two factors possibly combine? Researchers have identified vitamin D deficiencey as a risk factor for higher risk of Cesarean delivery in a woman's first birth. How big a risk are we talking about? Women with low vitamin D levels had almost FOUR times the risk of undergoing a C-section. Why did they only look at first births? Subsequent deliveries for someone who's had a Cesarean is complicated by decisions about whether or not to have another Cesarean. And, first births are often the most arduous for women - so if there is a effect from vitamin D deficiency, it's probably more likely to show up with primary births. The serious risks of C-sections are well documented (risks to both mother and baby). But if you're getting larger and larger with your first pregnancy, the idea of pushing a baby out may seem worse than getting a C-section. But God knows, it's definitely not. Vaginal delivery is the way to go, even for mother's comfort reasons. Keep in mind, a C-section combines recovering from labor/delivery/pregnancy, with recovering from major abdominal surgery. And doing both, all while caring for a fretful, never-sleeping newborn. Bottom line: The study has some pitfalls - especially since vitamin D deficiency possibly could be a marker for other types of taking-care-of-yourself issues. But making sure your vitamin D level is 75nmol/L or more is a nice, easy way to optimize health for yourself and your baby. And if it helps you and your baby dodge the C-section bullet, all the better.

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• Vital Signs: Having a Baby: Vitamin D Deficiency Is Tied to C-Sections (nytimes.com)

In an interesting twist on the vitamin D/breast cancer data, researchers interviewed breast cancer patients (and people who'd never had breast cancer) about their intake of vitamin D, cod liver oil, and sunshine. The study revealed that having gotten cod liver oil, vitamin D and sun exposure* from ages 10-19 is significantly associated with less chance of having breast cancer as an adult. Or, as the title explains, Early Vitamin D Intake Reduces Breast Cancer Risk. Reuters News reports: "Vitamin D from dietary intake and sunlight exposure early in life is associated with lower risks for both hormone receptor-positive breast cancers and hormone receptor-negative tumors, according to findings published in the October 15th issue of the American Journal of Epidemiology," (Am J Epidemiol 2008;168:915-924). Problems with the study? Mostly that it's based on recall (or remembering) what happened decades ago. Even so, the results are provocative, especially given the safety and other benefits from having an adequate vitamin D intake. So can we, as parents, do something NOW to protect teens against breast cancer? Consider giving your teen vitamin D supplements, cod liver oil, and/or mild, appropriate sun exposure. Having no breast cancer? Now there's a gift for life. *Sun, obviously, needs to be obtained in moderation - both because of the increased risks of skin cancer (and premature aging), as well as the fact that once you start burning, your body breaks down the vitamin D it has formed - defeating the whole purpose of mild sun exposure. Furthermore, if you live north of L.A./Atlanta, darkly-pigmented people actually cannot obtain enough vitamin D from the sun alone - most especially from November-May.

In a fun video opinion piece on Medscape, Dr. George Griffing tackled the slippery subject of cod liver oil. Was our mother's (and grandmother's) somewhat pushy advice to hold your nose and take it, foolish or informed? Here's how Dr. Griffing summarizes recent findings: "It turns out cod liver oil contains large amounts of vitamins A, D, and omega-3 fatty acids, and the health benefits may go beyond rheumatism and rickets.^[1] Vitamin A is essential for the immune system, bone growth, night vision, cellular growth, testicular and ovarian function. Pharmaceutical preparations are used to treat acne vulgaris and keratosis pilaris and to treat acute promyelocytic leukemia.^[2] Vitamin D not only prevents rickets but is also important for muscle function and may prevent type 1 diabetes, hypertension, and many common cancers.^[3-6] Fish oils include the omega-3 fatty acids (O3FA), eicosopentanoic acid, and docosahexaenoic acid (EPA and DHA). Recent evidence supports the cardiac benefits of O3FA, beginning in 1999 with publication of the GISSI study, which showed reduction of mortality and sudden death.^[7] Further data emerged from analysis of the Physicians Health Study, which showed a stepwise reduction in risk of sudden cardiac death based on blood levels of omega-3 fatty acids. Most recently, the Japanese EPA Lipid Intervention Study (JELIS) showed a reduction in coronary events. Sudden death was not affected, however, suggesting that the high fish intake in Japan may lower the baseline risk for this finding.^[8] The mechanism for fish oil protection has been speculated to be an improvement in lipids with a reduction in triglycerides and an increase in HDL and a direct membrane stabilizing effect of omega-3 fatty acids. The data are strong enough that European and American cardiac societies have incorporated EPA and DHA into their recent treatment guidelines for cardiac diseases. Cod liver oil is not for everyone, however. Cod liver oil is probably best avoided by pregnant women, asthmatics, and people taking anticoagulants such as warfarin." Go to the site to see Dr. Griffing's opinion for yourself. And here are those references:

1. Ross CM. Fish oil versus cod liver oil: is vitamin D a reason to go back to the future ^[comment]. J Am Board Fam Pract. 2005;18:445-446. Knight JA, Lesosky M, Barnett H, Raboud JM, Vieth R.
2. BODY Sanz MA. Treatment of acute promyelocytic leukemia. Hematology. 2006:147-155.
3. Vitamin D and reduced risk of breast cancer: a population-based case-control study. Cancer Epidemiol Biomarkers Prev. 2007;16:422-429.
4. Autier P, Gandini S. Vitamin D supplementation and total mortality. Arch Intern Med. 2007;167:1730-1737.
5. Giovannucci E. Can vitamin D reduce total mortality? Arch Intern Med. 2007;167:1709-1710.
6. Holick MF. High prevalence of vitamin D inadequacy and implications for health. Mayo Clinic Proceed. 2006;1:353-373.
7. Marchioli R, Barzi F, Bomba E, et al. GISSI-Prevenzione Investigators. Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infarction: time-course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione. Circulation. 2002;105:1897-1903.
8. Yokoyama M, Origasa H, Matsuzaki M, et al. Japan EPA Lipid Intervention Study (JELIS) Investigators. Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomised open-label, blinded endpoint analysis. Lancet. 2007;369:1090-1098.