Worldwide status of vitamin D nutrition Lips, P.
Journal of steroid biochemistry and molecular biology,
07/2010, Letnik:
121, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
The vitamin D status depends on the production of vitamin D3 in the skin under the influence of ultraviolet radiation and vitamin D intake through the diet or vitamin D supplements. The serum ...25-hydroxyvitamin D (25(OH)D) concentration is the parameter of choice for the assessment of vitamin D status. Low serum levels of calcium and phosphate and an elevated level of alkaline phosphatase can also point to vitamin D deficiency. Usually, between 50% and 90% of vitamin D in the body is coming from the production in the skin and the remainder is from the diet. The production of vitamin D3 in the skin depends on sunshine exposure, latitude, skin-covering clothes, the use of sun block and skin pigmentation. In general, serum 25(OH)D is lower with higher latitudes and with darker skin types, but there are exceptions. Vitamin D deficiency (serum 25(OH)D
<
25
nmol/l) is highly prevalent in India and China while vitamin D status is better in Japan and South-East Asia. Vitamin D deficiency is very common in the Middle-East and there is a relationship with skin covering clothes and staying outside of the sun. A poor to moderate vitamin D status is also common in Africa, probably caused by the dark skin types and cultural habits of staying outside of the sunshine. Vitamin D status is much better in North America where vitamin D deficiency is uncommon but vitamin D insufficiency (serum 25(OH)D between 25 and 50
nmol/l) is still common. In the United States and Canada milk is usually supplemented with vitamin D and the use of vitamin supplements is relatively common. Vitamin D status in Latin America usually is reasonable but there are exceptions and vitamin D insufficiency still occurs quite often. In Australia and New Zealand a poor vitamin D status was seen in the elderly who were often vitamin D deficient and also in immigrants from Asia. Vitamin D deficiency also occurred in children when the mother was vitamin D deficient. Within Europe, vitamin D status usually is better in the Nordic countries than around the Mediterranean. This may be due to a lighter skin and sun seeking behaviour and a high consumption of cod liver oil in the Northern countries while in Southern Europe people stay out of the sunshine and have a somewhat darker skin. A very poor vitamin D status was observed in non-western immigrants, especially in pregnant women.
In conclusion, vitamin D deficiency and insufficiency are globally still very common especially in risk groups such as young children, pregnant women, elderly and immigrants.
Vitamin D physiology Lips, P.
Progress in biophysics and molecular biology,
09/2006, Letnik:
92, Številka:
1
Journal Article
Recenzirano
Vitamin D3 is synthesized in the skin during summer under the influence of ultraviolet light of the sun, or it is obtained from food, especially fatty fish. After hydroxylation in the liver into ...25-hydroxyvitamin D (25(OH)D) and kidney into 1,25-dihydroxyvitamin D (1,25(OH)2D), the active metabolite can enter the cell, bind to the vitamin D-receptor and subsequently to a responsive gene such as that of calcium binding protein. After transcription and translation the protein is formed, e.g. osteocalcin or calcium binding protein. The calcium binding protein mediates calcium absorption from the gut. The production of 1,25(OH)2D is stimulated by parathyroid hormone (PTH) and decreased by calcium. Risk factors for vitamin D deficiency are premature birth, skin pigmentation, low sunshine exposure, obesity, malabsorption and advanced age. Risk groups are immigrants and the elderly. Vitamin D status is dependent upon sunshine exposure but within Europe, serum 25(OH)D levels are higher in Northern than in Southern European countries. Severe vitamin D deficiency causes rickets or osteomalacia, where the new bone, the osteoid, is not mineralized. Less severe vitamin D deficiency causes an increase of serum PTH leading to bone resorption, osteoporosis and fractures. A negative relationship exists between serum 25(OH)D and serum PTH. The threshold of serum 25(OH)D, where serum PTH starts to rise is about 75
nmol/l according to most surveys. Vitamin D supplementation to vitamin D-deficient elderly suppresses serum PTH, increases bone mineral density and may decrease fracture incidence especially in nursing home residents. The effects of 1,25(OH)2D and the vitamin D receptor have been investigated in patients with genetic defects of vitamin D metabolism and in knock-out mouse models. These experiments have demonstrated that for active calcium absorption, longitudinal bone growth and the activity of osteoblasts and osteoclasts both 1,25(OH)2D and the vitamin D receptor are essential. On the other side, bone mineralization can occur by high ambient calcium concentration, so by high doses of oral calcium or calcium infusion. The active metabolite 1,25(OH)2D has its effects through the vitamin D receptor leading to gene expression, e.g. the calcium binding protein or osteocalcin or through a plasma membrane receptor and second messengers such as cyclic AMP. The latter responses are very rapid and include the effects on the pancreas, vascular smooth muscle and monocytes. Muscle cells contain vitamin D receptor and several studies have demonstrated that serum 25(OH)D is related to physical performance. The active metabolite 1,25(OH)2D has an antiproliferative effect and downregulates inflammatory markers. Extrarenal synthesis of 1,25(OH)2D occurs under the influence of cytokines and is important for the paracrine regulation of cell differentiation and function. This may explain that vitamin D deficiency can play a role in the pathogenesis of auto-immune diseases such as multiple sclerosis and diabetes type 1, and cancer. In conclusion, the active metabolite 1,25(OH)2D has pleiotropic effects through the vitamin D receptor and vitamin D responsive elements of many genes and on the other side rapid non-genomic effects through a membrane receptor and second messengers. Active calcium absorption from the gut depends on adequate formation of 1,25(OH)2D and an intact vitamin D receptor. Bone mineralization mainly depends on ambient calcium concentration. Vitamin D metabolites may play a role in the prevention of auto-immune disease and cancer.
Vitamin D status is highly different in various countries of Europe, the Middle East and Asia. For this review, vitamin D deficiency is defined as serum 25-hydroxyvitamin D (25(OH)D) <25nmol/l. ...Within European countries, serum 25(OH)D is <25nmol/l in 2–30% of adults, increasing in the elderly and institutionalized to more than 80% in some studies. A north-south gradient was observed for serum 25(OH)D in the Euronut and MORE studies with higher levels in Scandinavia and lower levels in Italy and Spain and some Eastern European countries. This points to other determinants than sunshine, e.g. nutrition, food fortification and supplement use. Mean vitamin D intake in Scandinavia is 200–400IU/d, twice that in other European countries. Very low serum 25(OH)D levels have been reported in the Middle East, e.g. Turkey, Lebanon, Jordan and Iran. In these countries serum 25(OH)D was lower in women than in men and associated with clothing habits. In a Lebanese survey, vitamin D deficiency was observed in the majority and occurred mainly in veiled women. In India, vitamin D deficiency was observed in more than 30%, vitamin D status being poor in school children, pregnant women and large cities. Vitamin D status was much better in Malaysia and Singapore, but lower serum 25(OH)D was observed in Japan and China. Rickets and osteomalacia appear quite common in India, but precise data are lacking. Immigrants in Europe from the Middle East and Asia carry a high risk for vitamin D deficiency, pregnant women being especially at risk. Comparison of vitamin D status between countries is hampered by interlaboratory variation of serum 25(OH)D measurement. In addition, there is a need of population-based data. In conclusion, vitamin D deficiency is common in Southern Europe, the Middle East, India, China and Japan. It is less common in Northern Europe and Southeast Asia. Risk groups are young children, the elderly, pregnant women and non-western immigrants in Europe. Important determinants are skin type, sex, clothing, nutrition, food fortification, supplement use, BMI and degree of urbanization.
Muscle strength plays an important role in determining risk for falls, which result in fractures and other injuries. While bone loss has long been recognized as an inevitable consequence of aging, ...sarcopenia—the gradual loss of skeletal muscle mass and strength that occurs with advancing age—has recently received increased attention. A review of the literature was undertaken to identify nutritional factors that contribute to loss of muscle mass. The role of protein, acid–base balance, vitamin D/calcium, and other minor nutrients like B vitamins was reviewed. Muscle wasting is a multifactorial process involving intrinsic and extrinsic alterations. A loss of fast twitch fibers, glycation of proteins, and insulin resistance may play an important role in the loss of muscle strength and development of sarcopenia. Protein intake plays an integral part in muscle health and an intake of 1.0–1.2 g/kg of body weight per day is probably optimal for older adults. There is a moderate inverse relationship between vitamin D status and muscle strength. Chronic ingestion of acid-producing diets appears to have a negative impact on muscle performance, and decreases in vitamin B
12
and folic acid intake may also impair muscle function through their action on homocysteine. An adequate nutritional intake and an optimal dietary acid–base balance are important elements of any strategy to preserve muscle mass and strength during aging.
To compare vitamin D status in women with PCOS versus fertile women and subsequently evaluate the association between vitamin D status and metabolic disturbances in PCOS women.
We conducted a ...cross-sectional comparison study of 639 women with PCOS and 449 fertile women. Serum 25-hydroxyvitamin D (25(OH)D) was stratified into a severe deficient (< 25 nmol/l), insufficient (25-50 nmol/l), moderate (50-75 nmol/l) and adequate (> 75 nmol/l) status. The main outcome measures were the difference in vitamin D status between PCOS and fertile women, and the association between serum 25(OH)D and metabolic disturbances in PCOS women only.
Serum 25(OH)D was significantly lower in PCOS women compared to fertile controls (mean 25(OH)D of 49.0 nmol/l versus 64.5 nmol/l). An adjusted significant difference was seen between serum 25(OH)D and homeostasis model assessment (HOMA-IR) (β = 0.76; 95% CI: 0.63-0.91; p < 0.01), HDL-cholesterol (β = 0.20; 95% CI: 0.05-0.60, p < 0.01) and apolipoprotein A1 (β = 26.2; 95% CI: 7.5-45.0, p < 0.01) between the highest vitamin D group compared to the lowest vitamin D group.
This study demonstrates that women with PCOS have a significantly lower serum 25(OH)D compared to fertile controls. A compromised vitamin D status in PCOS women is associated with a higher HOMA-IR and an unfavourable lipid profile. Large randomized controlled trials are necessary to explore the causality of this linkage.
It has been hypothesized that hypovitaminosis D is associated with depression but epidemiological evidence is limited. We investigated the association between depressive disorders and related ...clinical characteristics with blood concentrations of 25-hydroxyvitamin D 25(OH)D in a large cohort. The sample consisted of participants (aged 18-65 years) from the Netherlands Study of Depression and Anxiety (NESDA) with a current (N=1102) or remitted (N=790) depressive disorder (major depressive disorder, dysthymia) defined according to DSM-IV criteria, and healthy controls (N=494). Serum levels of 25(OH)D measured and analyzed in multivariate analyses adjusting for sociodemographics, sunlight, urbanization, lifestyle and health. Of the sample, 33.6% had deficient or insufficient serum 25(OH)D (<50 nmol l(-1)). As compared with controls, lower 25(OH)D levels were found in participants with current depression (P=0.001, Cohen's d=0.21), particularly in those with the most severe symptoms (P=0.001, Cohen's d=0.44). In currently depressed persons, 25(OH)D was inversely associated with symptom severity (β=-0.19, s.e.=0.07, P=0.003) suggesting a dose-response gradient, and with risk (relative risk=0.90, 95% confidence interval=0.82-0.99, P=0.03) of having a depressive disorders at 2-year follow-up. This large cohort study indicates that low levels of 25(OH)D were associated to the presence and severity of depressive disorder suggesting that hypovitaminosis D may represent an underlying biological vulnerability for depression. Future studies should elucidate whether-the highly prevalent-hypovitaminosis D could be cost-effectively treated as part of preventive or treatment interventions for depression.
This position paper of the International Osteoporosis Foundation makes recommendations for vitamin D nutrition in elderly men and women from an evidence-based perspective.
Summary This review describes the vitamin D status in different regions of the world with the objective of understanding the scope of hypovitaminosis D and the factors related to its prevalence that ...may contribute to the pathogenesis of osteoporosis and fragility fractures. Introduction Vitamin D status has been linked to the pathogenesis of hip fractures as well as other skeletal and non-skeletal disorders. The purpose of this review is to provide a global perspective of vitamin D status across different regions of the world and to identify the common and significant determinants of hypovitaminosis D. Methods Six regions of the world were reviewed—Asia, Europe, Middle East and Africa, Latin America, North America, and Oceania—through a survey of published literature. Results The definition of vitamin D insufficiency and deficiency, as well as assay methodology for 25-hydroxyvitamin D or 25(OH)D, vary between studies. However, serum 25(OH)D levels below 75 nmol/L are prevalent in every region studied whilst levels below 25 nmol/L are most common in regions such as South Asia and the Middle East. Older age, female sex, higher latitude, winter season, darker skin pigmentation, less sunlight exposure, dietary habits, and absence of vitamin D fortification are the main factors that are significantly associated with lower 25(OH)D levels. Conclusion Reports from across the world indicate that hypovitaminosis D is widespread and is re-emerging as a major health problem globally.
Objective Human aging is accompanied by a decrease in growth hormone secretion and serum insulin-like growth factor (IGF)-1 levels. Also, loss of muscle mass and strength and impairment of physical ...performance, ending in a state of frailty, are seen in elderly. We aimed to investigate whether handgrip strength, physical performance and recurrent falls are related to serum IGF-1 levels in community-dwelling elderly. Design Observational cohort study (cross-sectional and prospective). Methods We studied the association between IGF-1 and handgrip strength, physical performance and falls in participants of the Longitudinal Aging Study Amsterdam. A total of 1292 participants were included (633 men, 659 women). Serum IGF-1 levels were divided into quartiles (IGF-1-Q1 to IGF-1-Q4). Data on falls were collected prospectively for a period of 3 years. All analyses were stratified for age and physical activity and adjusted for relevant confounders. Results Men with a low physical activity score in IGF-1-Q1 and IGF-1-Q2 of the younger age group had a lower handgrip strength compared to IGF-1-Q4. In younger more active males in IGF-1-Q2 physical performance was worse. Recurrent fallers were less prevalent in older, low active males with low IGF-1 levels. In females, recurrent fallers were more prevalent in older, more active females in IGF-1-Q2. IGF-1 quartile may predict changes in handgrip strength and physical performance in men and women. Conclusions Our results indicate that lower IGF-1 levels are associated with lower handgrip strength and worse physical performance, but less recurrent fallers especially in men. Associations were often more robust in IGF-1-Q2. Future studies on this topic are desirable.
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