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Vitamin D: Have You Got Sunshine On A Cloudy Day?

20 Jan 2012 08:12:48 AM

- Its Health Benefits and Links to Cancer Risks

It’s been well known that vitamin D, along with good calcium levels, plays an important role in building strong bones and teeth. But did you know Vitamin D offer many more health benefits and good levels of vitamin D can lower your cancer risk?

Worldwide, it is estimated that 1 billion people have vitamin D deficiency or insufficiency. 1 A study conducted in Asia concluded that low vitamin D level is a common but largely ignored health problem in Hong Kong. Test results showed 63% of the subjects had vitamin D below the recommended level (30ng/mL), which is required for general health.2,3

The Sunshine Vitamin
Sun exposure on bare skin is the major source of vitamin D, which is synthesized in the body when we are under the sun. Alternatively, we can consume vitamin D rich foods and supplements, but adequate levels cannot be obtained from the diet alone. In Hong Kong, during winter, we would need approximately 45 minutes of exposure on the arms, legs, face and hands every other day to get adequate vitamin D. If you are like most people who work in an office with tinted windows, chances are that you will need oral supplementation to reach the recommended levels:

400 – 1,000 IU daily for children
800 – 2,000 IU daily for adults1

Benefits and the Importance of Vitamin D:
Vitamin D has important effects far beyond the bone benefits. Not only is vitamin D known to help reduce your risk of osteoporosis, rickets or bone fracture, scientists have found about 3,000 genes that are responsive and triggered by vitamin D. This is why vitamin D functions in so many different tissues, and affects such a large number of different health conditions, such as heart disease, inflammation and cancers.

Vitamin D Top 10 facts:

1) Fortifies bone and muscle strength
Vitamin D deficiency causes muscle weakness and pain in children and adults.7 In children these are often called “growing pains”. In a study of 150 consecutive patients with persistent, nonspecific musculoskeletal pain, 93% of them had vitamin D deficiency.8

Vitamin D supplementation can help decrease the incidence of low bone density, and in turn, fractures and osteoporosis especially in the elderly. 1,000 IU of Vitamin D3 with 600mg Calcium has been shown to reduce fractures in older women by a whopping 75%.

A study showed that supplementation of vitamin D with calcium increased muscle strength and decreased the risk of falling by almost 50% compared to supplementation with calcium alone.7 

2) Increases immunity
Children with vitamin D deficiency have more than twice as many colds each year as those with adequate levels. Their infections are not as wheezy, and require less hospitalizations. Evidence indicates that vitamin D-mediated innate immunity is important in host defenses against respiratory tract pathogens. Vitamin D is needed for full immunity.

Studies showed that vitamin D deficiency of the newborn increases risk of respiratory infections, by 216% in the period up to 5 years old. Wheezing is also increased.9 There is also a six times higher risk of developing Respiratory Syncytial Virus (RSV) during their first year of life. Pregnant mothers and breast feeding mothers are advised to take 2,000 IU of vitamin D daily. Alternatively the infant is to be supplemented 600-1,000IU daily. Breast milk does not provide adequate vitamin D.

3) Reduces inflammation
Vitamin D reduces inflammation by increasing the response of the anti-inflammation cells and reduces those of the pro-inflammatory.

4) Reduces allergy
Research showed vitamin D insufficiency was linked to a 50% increase in the risk of severe asthma attacks requiring hospitalization. Higher Vitamin D intake by pregnant mothers reduces asthma risk by as much as 40% in children 3 to 5 years old.10

5) Improves our anti-cancer fighting chemistry
It reduces breast cancer very significantly. People with the highest serum vitamin D levels had a 50% reduced risk of breast and colorectal cancer.11,12 A large number of studies indicate that vitamin D can inhibit cell proliferation and promote apoptosis and cell differentiation in breast tumor tissue. Meanwhile, men with the highest levels of vitamin D had significantly lower overall risk (45%) of prostate cancer.13

6) Protects against cardiovascular diseases
Vitamin D is important for blood pressure regulation. It has a protective effect against arterial stiffness and also inhibiting vascular smooth muscle growth. Low vitamin D level can cause cardiovascular diseases including hypertension14 and the hardening of artery walls 15, while adequate levels are associated with reduced stroke risk.

7) Reduces bone and tooth loss
Optimal level of vitamin D can reduce calcium loss from the bones by enhancing the calcium absorption from our intestine, and increased retention of calcium in the kidney. Peridontal disease damage to teeth is also reduced. Vitamin D also slows down the bone loss rate in menopausal women by enhancing the Calcium reserve in the body.

8) Reduces incidence of auto-immune diseases
Low vitamin D level can result in cellular imbalance and triggers the onset of the autoimmune diseases. 16 They are consequences of our dysfunctional immune response that mistakenly recognizes our own body parts as foreign substances. This leads to a series of self-attacking mechanisms causing defects in our body. Examples are Rheumatoid Arthritis, Multiple Sclerosis, and Type-1 Diabetes.

9) Reduces aging
Low vitamin D level is associated with physiological aging of skin.19 Apart from skin, it also has its effects on many aspects: Cardiovascular, respiratory, muscular, skeletal, metabolic, digestive, neurological, and sensory systems.

10) Decreases preeclampsia, birthing problems, and sustains healthy fetal growth
Recent research concluded maternal vitamin D deficiency as a strong, independent risk factor for preeclampsia,20 a pregnancy-induced hypertension that could force premature delivery. Low vitamin D levels during pregnancy has also been linked with a number of health problems in the offspring such as impaired growth, skeletal problems and Type-1 diabetes.21

Are You at Risk of Vitamin D Deficiency?
Answer the following questions:
1) Do you spend a considerable amount of time away from outdoors sun exposure?
2) Do you overprotect yourself with thick clothing and sunscreen?
3) Are you over the age of 50?
4) Are you pregnant or a lactating mother

If you answer YES to any of the questions above, you may be at risk. But don’t worry, as mentioned earlier, the deficiency is not uncommon and you can take oral supplementation. It is important that you choose a high-quality vitamin D supplement to ensure an adequate amount is absorbed into the body. The best way to determine your optimal dose is to get your blood tested.

IMI dispensary and practitioners will be able to give you advice on vitamin D supplementation and testing, please visit our dispensary or call 2523 7121.

Reference:
1. Holick MF. Vitamin D deficiency. N Engl J Med 2007; 357:266-281
2. Vieth R, et al. The urgent need to recommend an intake of Vitamin D that is effective. Am J Clin Nutr 2007; 85:649-650
3. Wat WZ, Leung JY, Tam S, Kung AW. Prevalence and impact of vitamin D insufficiency in southern Chinese adults, Ann Nutr Metab 2007; 51(1):59-64
4. Khosla S , Melton LJ.Osteopenia. New Engl J Med 2007;356:2293-2300
5. Vasquez G, Boland R, De Boland A. Stimulation of Ca2+ release-activated Ca2+ channels as a potential mechanism involved in non-genomic 1,25(OH)2-vitamin D3-induced CA2+ entry in skeletal muscle cells. Biochem Biophys Res Commun 1997; 239:562–565
6. Bischoff HA, Stahelin HB, Dick W, et al. Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial. J Bone Miner Res. 2003;18(2):343-351.
7. Bringhurst FR, Demay MB, Kronenberg HM. Mineral Metabolism. In: Larson PR, Kronenberg HM, Melmed S, Polonsky KS, eds. Larsen: Williams Textbook of Endocrinology: Elsevier; 2003:1317-1320.)
8. Plotnikoff GA, Quigley JM. Prevalence of severe hypovitaminosis D in patients with persistent, nonspecific musculoskeletal pain. Mayo Clin Proc. 2003;78(12):1463-1470.
9. PEDIATRICS Vol. 127 No. 1 January 1, 2011.
10. Litonjua AA, Weiss ST. Is vitamin D deficiency to blame for the asthma epidemic? J Allergy Clin Immunol 2007;120:1031–1035.
11. Lappe JM, Travers-Gustafason D, Davies KM, et al. Vitamin D and calcium supplementation reduces cancer risk: results of randomized trial. Am J Clin Nutr.2007;85:1586-1591
12. Dembrow M. High vitamin D: Rx for cancer prevention? Clin Advisor 2007; 10:54-57
13. Li H, Stampfer MJ, Hollis JBW, Mucci LA, Gaziano JM, et al. A prospective study of plasma vitamin D metabolites, vitamin D receptor polymorphisms, and prostate cancer. PLoS Med 2007; 4(3): e103
14. Rostand, S.G. Ultraviolet light may contribute to geographic and racial blood pressure differences. Hypertension 1997; 30: 150-156
15. Simpson, R.U. & Weishaar, R.E. Involvement of 1,25-dihydroxyvita-min D3 in regulating myocardial metabolism: physiological and pathological actions. Cell Calcium 1988; 9: 285-292
16. Catorna MT , Zhu Y , Froicu M , et al.Vitamin D status, 1,25-dihydroxyvitmin D3, and the immune system. Am J Clin Nutr 2004;80(Suppl):1717S-1720S
17. Ponsonby A-L, McMichael A, van der Mei I. Ultraviolet radiation and autoimmune disease: insights from epidemiological research. Toxicology 2002; 181-182:71-8.
18. VanAmerongen BM, Dijkstra CD, LipsP, Polman CH. Multiple sclerosis and vitamin D: an update. Eur J Clin Nutr 2004; 58:1095-109.
19. Keisala T, Misayan A, Lou YR, Zou J, Kalueff A, Pyykko I, et al. Premature aging in vitamin D receptor mutant mice, Journal of Steroid Biochemistry and Molecular Biology 2009; 115: 91-97
20. Bodnar LM, Catov JM, Simhan HN, Holick MF, Powers RW, Roberts JM. Maternal vitamin D deficiency increases the risk of preeclampsia. J Clin Endocrinol Metab 2007; 92:3517-3522
21. Holick MF. Resurrection of vitamin D deficiency and rickets. J Clin Invest 2006; 116:2062–2072