http___metro-portal.hr_pretilost-uzrokuje-manjak-vitamina-d_77539_1.xml
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With the arrival of Fall, there are going to be changes in our daily routine. School is back in session and we may find ourselves spending more time inside working and catching up on what didn’t get done during the energetic summer season. Winter will be a few months away, the days will get shorter, and we will naturally be indoors more to avoid the cold that will (eventually) come. More time inside means less time in the sun. Less time in the sun can mean a shift in our vitamin D status…and vitamin D status has implications for our health. Vitamin D is a fat-soluble vitamin that is important for a number of cellular processes in our bodies. It plays a significant role in calcium balance and bone metabolism. We need vitamin D in order to absorb other nutrients from our gut. Vitamin D helps muscles work, the immune system function, cells differentiate, and it is involved in the balance of hormones such as insulin. Very few foods naturally contain vitamin D. We can get some from fatty fish, for example, or foods specifically fortified with the vitamin. Most vitamin D is obtained from synthesis in the skin. When our skin is exposed to UVB from the sun, precursors of vitamin D are formed that enter a cascade of enzymatic reactions in the liver and kidney to become the active form of the vitamin used by the body. Because of food fortification, profound vitamin D deficiency is rare in developed countries. Subclinical vitamin D deficiency, however, is very common. Research has shown that fifty percent of the adult population in America is deficient in vitamin D. Some experts have even estimated that up to ninety percent of adults may have some degree of deficiency. People can become deficient in vitamin D for a number of reasons. Because our primary source of vitamin D comes from sun exposure, levels tend to decline in the winter months when we cover ourselves up and spend more time indoors. People with darker skin are at greater risk of vitamin D deficiency because the pigment in their skin does not absorb as many UV rays. Those who have difficulty absorbing fat (for example, in Celiac Disease, Crohn’s Disease, or pancreatic insufficiency) are more likely to have low levels of vitamin D. Being of older age, obesity, taking certain medications, or being hospitalized are all risk factors for vitamin D deficiency. Some well-known complications of vitamin D deficiency are osteoporosis and fractures. Associations have also been made between vitamin D deficiency and cancer, infections, autoimmunity, and cardiovascular disease. Those with lower vitamin D levels may have muscle weakness and be more likely to fall. People who are deficient in vitamin D may complain of fatigue or musculoskeletal pain. Those with low vitamin D levels score lower on mini-mental status exams, a test used for evaluation of dementia. Vitamin D status of the mother appears to affect pregnancy outcomes. It has even been hypothesized that the drop in vitamin D that occurs in the winter months may be somewhat responsible for the increase in infections, like the cold and flu, during that time of year. Vitamin D status can be easily determined by a blood test called 25-hydroxy Vitamin D. The optimal vitamin D level, however, is not known. Deficiency is typically defined as a serum level of less than 20 ng/mL and excess as greater than 100 ng/mL. A reasonable target serum level in most healthy adults is 50 ng/mL. The Recommended Daily Allowance (RDA) of vitamin D for adults is 600-800 IU. Fifteen minutes of daily sun exposure may be adequate for maintaining a normal vitamin D level. If your vitamin D is not optimal, supplementation is easily available over-the-counter. Testing for vitamin D is widely available and usually affordable, but if you are without insurance, have a high deductible, or find that your insurance policy does not cover this test, many accessible commercial laboratories have reasonable cash pricing (approximately $20). As always, the answer to optimal health does not lie in one vitamin, mineral, food, or practice. Vitamin D is, however, important for the balance of health. Ask your doctor about testing vitamin D as part of your health maintenance evaluation and have the discussion about the optimal level for you and how you can reach it.
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Debljina uzrokuje manjak vitamina D Poznato je da debjina utječe na utječe na razvoj dijabetesa tipa 2, srčanih bolesti i određenih oblika raka U nedavnom izdanju časopisa PLoS Medicine objavljena je studija koja upozorava da debljina može uzrokovati manjak vitamina D. Ova je studija, koju su proveli istraživači okupljeni u zajedničkoj suradnji pod imenom D-CarDia u okviru Britanske zaklade za srce (British Heart Foundation), prva povezala visok indeks tjelesne mase (BMI) s niskim razinama vitamina D. Studija je obuhvatila više od 42.000 ljudi iz 21 zemlje, a unutar nje istraživači su pokušali prepoznati sve genetske varijacije kojr bi mogle biti povezane s indeksom tjelesne mase i vitaminom D kako bi bili sigurni da nijedan drugi čimbenik nije utjecao na rezultate. Visok indeks tjelesne mase povezan s niskim razinama vitamina D Istraživači su otkrili da je povezanost između visokog indeksa tjelesne mase i niskih razina vitamina D svojstvena svim demografskim skupinama. Svako povećanje indeksa tjelesne mase za 10 posto uzrokovalo je padom razine vitamina D od 4,2 posto. „Pokazali smo da je povezanost između indeksa tjelesne mase i vitamina D prisutna kod svih bijelaca Sjeverne Amerike i Europe bez obzira na dob ili spol. Dokazali smo i da povećanje indeksa tjelesne mase dovodi do smanjenja vitamina D, a time i da pretilost predstavlja rizik za nedostatak vitamina D", izjavili su autori, podsjećajući kako je vitamin D nužan za zdravlje kostiju i sprečavanje bolesti poput raka, dijabetesa i visokog krvnog tlaka. Nedavno istraživanje provedeno na Sveučilištu u Kopenhagenu otkrilo je kako niske razine vitamina D mogu povećati rizik obolijevanja od srčanih bolesti i prerane smrti. „Naša studija ističe nužnost povećanja razine vitamina D kod pretilih osoba, kao i važnost praćenja i tretiranja nedostatka vitamina D kako bi se smanjili nepovoljni učinci pretilosti na zdravlje. Smanjenje pretilosti u populaciji trebalo bi dovesti i do smanjenja učestalosti nedostatka vitamina D", izjavili su autori istraživanja. Debljina i niske razine vitamina D povezane su s rizikom od dijabetesa Moguće je i da bi pretilost mogla utjecati, osim na smanjenje razine vitamina D, i na razvoj dijabetesa tipa II. Istraživači su otkrili da je rizik za razvoj inzulinske rezistencije veći kod osoba koje su i pretile i imaju nizak vitamin D, nego kod osoba kod kojih je samo jedan od tih dvaju čimbenika izražen. Shaum Kabadi i njegov tim sa Sveučilišta Dextrel otkrili su kako pretili ljudi s normalnom razinom vitamina D imaju čak 20 puta veći rizik za razvoj inzulinske rezistencije u usporedbi s ostatkom populacije. No, rizik kod pretilih ljudi s niskom razinom vitamina D veći je čak 32 puta.