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- By Liza Torborg Mayo Clinic Q and A: Getting enough vitamin D DEAR MAYO CLINIC: It seems that vitamin D is always in the news. Why is it so important, and does the average person need a vitamin D supplement? ANSWER: Vitamin D is an essential nutrient that your body requires primarily to build strong bones. It does this by helping your body absorb and maintain adequate levels of two other nutrients important to bone health — calcium and phosphate. You get most of your vitamin D from sunlight. When ultraviolet (UV) rays hit your skin — particularly midday — it triggers production of vitamin D. People in climates with more sunlight tend to get more exposure than do those in climates with less sunlight. Certain foods — fortified foods, such as milk and cereal, and fatty fish, such as salmon, tuna and mackerel — also provide vitamin D. Chemical reactions in your liver and kidneys transform vitamin D into forms that your body can use. In general, adults should consume 600 international units of vitamin D a day. That goes up to 800 international units a day for those over 70. National survey data indicate that most Americans don’t get enough vitamin D through their diets. However, the data also indicate that average blood levels of vitamin D are above what’s considered necessary for good bone health for most people. This implies that most American adults get enough vitamin D — most likely through sun exposure. Severe and prolonged vitamin D deficiency is known to cause bone mineralization disorders such as rickets in children and osteomalacia in adults. Conditions such as these can lead to soft bones, aching muscles, painful movement and fractures. Vitamin D deficiency also may contribute to osteoporosis. Although numerous studies have reported results associating vitamin D deficiency with various other diseases and conditions — such as fatigue, depression, chronic pain, heart disease, autoimmune disorders, infections, metabolic issues and cancer — clinical trials of vitamin D supplements in people with these conditions generally have failed to show benefit. This implies that a lack of vitamin D probably isn’t causing these conditions. Some experts argue that rather than being a cause of these kinds of illnesses, vitamin D deficiency may be a biological marker for them, signaling the presence of inflammatory processes related to the disease or condition. Adults who may not get enough vitamin D generally fail to do so due to one or more of these reasons: - Chronic condition Conditions that affect your absorption or processing of vitamin D can affect circulating levels of the vitamin. For example, having conditions such as inflammatory bowel disease or celiac disease, or having had bariatric surgery can affect your intestine’s ability to absorb vitamin D. Obesity appears to drive down, or perhaps dilute, levels of circulating vitamin D. Chronic kidney or liver problems can interfere with the conversion of vitamin D into its active circulating forms, as can certain drugs, such as anti-convulsants and glucocorticoids. - Reduced skin synthesis People with darker skin are at greater risk of vitamin D deficiency because greater amounts of melanin in the skin reduce the skin’s ability to produce vitamin D from sunlight. Aging also decreases the efficiency of vitamin D synthesis. Sunscreen, clothing and other UV protective measures that block skin’s exposure to the sun not only help prevent skin cancer, but also reduce production of vitamin D. - Limited sun exposure People who spend most of their time indoors generally have low levels of vitamin D. The amount of sun exposure needed for adequate vitamin D production is uncertain, but most estimates are no more than 15 minutes a day between 10 a.m. and 3 p.m., three times a week. However, this sun exposure must be balanced against your risk of skin cancer. Most healthy American adults have adequate levels of vitamin D. But if you fall into a risk category, talk to your health care provider about whether you need a supplement. Generally, a blood test isn’t necessary because taking the recommended amount of vitamin D as a supplement will ensure adequate levels in most people. Even 600 international units a day will correct a deficiency fairly quickly. However, taking too much vitamin D can overly increase your absorption of calcium, leading to problems such as kidney stones and damage to your heart and blood vessels. The National Academy of Medicine recommends an upper limit of 4,000 international units a day to be safe. (adapted from Mayo Clinic Health Letter) — Dr. Sundeep Khosla, Endocrinology, Mayo Clinic, Rochester, Minnesota
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Nedostaje vam vitamina D? Unesite ga u organizam uz pomoć ovih 5 namirnica Muči li vas pospanost, loše raspoloženje i visok krvni tlak? Svi navedeni simptomi bi mogli upozoravati na manjak vitamina D u organizmu. Osim izlaganja sunčevim zrakama, vitamin D možete dobiti i iz nekih namirnica. Vitamin D (kalciferol) se iz povijesnih razloga svrstava u vitamine, zapravo je naziv sa skupinu prohormona, topljivih u mastima. Međutim, u slučaju nedovoljnog izlaganja suncu, vitamin D je vitamin tj. esencijalna komponenta hrane. Još se naziva i antirahitični vitamin te vitamin sunca. Procijenjeno je da se ljeti u jednom četvornom centimetru kože, koja se izlaže suncu, svaki sat proizvede 6 IU vitamina D. Također se procijenjuje da po zimi koža stvara 75% manje vitamina D nego ljeti odnosno izlaganjem suncu zimi, proizvede se oko 200 IU vitamina D u dva sata. Losos za večeru Iako se vitamin D nalazi u dosta malo namirnica, jedan od najboljih izvora je vitamin D su masne ribe poput lososa i sardina. Volite li jesti lososa, jedan filet za večeru će vam osigurati potrebnu količinu ovog vitamina. U žumanjku jajeta se nalazi vitamin D, no kako sadrži i kolesterol, ne pretjerujte s konzumacijom. Jaja možete pripremiti za doručak, narezati ga u salatu ili od njega pripremiti neki ukusan desert. Vitaminom D je bogata i tuna iz konzerve koja je svakako jeftinija od svježe ribe pa ju možete konzumirati umjesto lososa. Mlijeko Pojedine vrste sojinog i rižinog mlijeka sadrže jednaku količinu vitamina D kao i kravlje mlijeko, pa imate izbora ako ne podnosite laktozu. Ako radije svoj vitamin D uzimate putem dodataka prehrani, stručnjaci savjetuju da ovo činite uz najveći obrok. Ovako ćete povećati njegovu apsorpciju za čak 50 % . Brojne funkcije vitamina D u organizmu Najvažnija je da održava homeostazu kalcija u tijelu. Vitamin D ima zadaću kontrolirati koliko će se kalcija apsorbirati iz hrane, koliko će se ugrađivati ili oslobađati iz kostiju. Ukoliko u organizmu nedostaje kalcija, proizvodi se više aktivnog oblika vitamina D u bubrezima koji pomaže apsorbciju kalcija. Ukoliko nedostaje vitamina D u organizmu, navedeni mehanizam neće osigurati homeostazu kalcija te će doći do oslobađanja kalcija iz kostiju, tj. do demineralizacije, kako bi se postigla potrebna razina kalcija u krvi. Navedeno stanje dovodi do osteomalacije i osteoporoze u odraslih ljudi te rahitisa u djece (antirahitični vitamin). Zbog toga, uz dovoljan unos vitamina D, moramo imati na umu da zadovoljimo i dnevne potrebe za kalcijem. Osim navedene uloge u oragnizmu, vitamin D ima i druge funkcije poput regulacije fosfatnog metabolizma, regulacije imunološkog odgovora, regulacije razine inzulina i šećera u krvi te krvnog tlaka. Sličan Post 2016-11-10 06:42:00. izvor: Kako Leciti