Re: Vitamin D review

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Clinics in Geriatric MedicineVolume 19 • Number 2 • May 2003Copyright © 2003 W. B. Saunders Company

Calcium, vitamin D, and nutrition in elderly adultsVitamin D

Vitamin D deficiency is associated with rickets, osteoporosis, muscle weakness, and decreased immune function [10] . Plasma levels of calcidiol (25-hydroxycholecalciferol) have been used to define vitamin D status as low (< 100 nmol/L), insufficient (25–50 nmol/L), or deficient (< 25 nmol/L). Vitamin D is cutaneously synthesized after exposure to sunlight and is also obtained from the diet as either ergocalciferol or cholecalciferol. Vitamin D is hydroxylated in the liver to calcidiol and then to the active metabolite calcitriol (1a,25-dihydroxycholecalciferol) in the kidney. Calcitriol is the most active metabolite of Vitamin D, and specific receptors are found in the kidney, intestine, and bone [18] . Its primary function is to increase active intestinal calcium absorption.

In younger individuals, vitamin D synthesis in the skin is the primary determinant of serum calcidiol levels; this cutaneous synthesis is reduced in elderly individuals. Elevations in serum parathyroid hormone (PTH) and greater bone loss are often associated with lower levels of calcidiol. Vitamin D insufficiency is believed to play a strong role in osteoporosis. The current US Dietary Reference Intake (DRI) from the National Academy of Sciences recommendation for vitamin D intake in persons aged 51 to 70 years is 10 µg per day (400 IU/day), and the recommended intake for those older than 70 years is 15 µg per day (600 IU/day; see Table 1 ). Higher doses of vitamin D (800–1000 IU/day) in elderly persons (age, = 65 years) may be required for optimal bone health. These higher vitamin D doses (in combination with calcium) have been shown to reduce fracture risk in this population. Rich natural sources of vitamin D include fatty fish, fish liver oils (eg, cod liver oil), and liver. Several foods are also fortified with vitamin D, including milk (eg, cow, soy, and rice milk), some yogurts, cereals, nutrition bars, and margarine.

Summary

The nutritional needs for optimizing bone health easily can be met by a diet that is high in fruits and vegetables (five or more servings/day), adequate in protein but moderate in animal protein, and with adequate calcium and vitamin D intakes through the consumption of low fat dairy or calcium-fortified foods. Foods are a preferred source to maintaining calcium balance because there are other essential nutrients that are found in high-calcium foods. For those individuals in whom there is inadequate calcium intake from diet, supplemental calcium can be used. Supplemental or dietary calcium should be spread out throughout the day, with 500 mg or less being consumed at each meal to optimize absorption.

In all individuals older than 70 years, vitamin D intakes of at least 600 IU per day (up to 1000 IU/day) are recommended, in addition to the calcium requirement of 1200 mg per day. Vitamin D from foods, supplements, and/or multivitamins can be used to meet the vitamin D requirement.

In frail elderly individuals with malabsorption and alcoholics, there may be a need to supplement magnesium. Some elderly individuals with indications of poor nutritional status (low albumin levels) or after hip fracture might benefit from protein supplementation and a multivitamin to ensure adequacy of other nutrients.

RE: [ ] Another Vitamin D Benefit

One more..>> I recall some suggestions as high as 4000 IU. Additionally, we also now realize that the Food and Nutrition Board's previouslydefined Upper Limit (UL) for safe intake at 2,000 IU/day was setfar too low and that the physiologic requirement for vitamin D inadults may be as high as 5,000 IU/day, which is less than half ofthe >10,000 IU that can be produced endogenously with full-bodysun exposure.1,21. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Am JClin Nutr. 1999;69(5):842-56.2. Heaney RP, Davies KM, Chen TC, Holick MF, Barger-Lux MJ. Human serum 25-hydroxycholecalciferolresponse to extended oral dosing with cholecalciferol. Am J Clin Nutr.2003;77(1):204-10.http://www.bioticsresearch.com/PDF/Vitamin%20D%20ATHM2004%20Vasquez.pdf

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Clinics in Geriatric MedicineVolume 19 • Number 2 • May 2003Copyright © 2003 W. B. Saunders Company

Calcium, vitamin D, and nutrition in elderly adultsVitamin D

Vitamin D deficiency is associated with rickets, osteoporosis, muscle weakness, and decreased immune function [10] . Plasma levels of calcidiol (25-hydroxycholecalciferol) have been used to define vitamin D status as low (< 100 nmol/L), insufficient (25–50 nmol/L), or deficient (< 25 nmol/L). Vitamin D is cutaneously synthesized after exposure to sunlight and is also obtained from the diet as either ergocalciferol or cholecalciferol. Vitamin D is hydroxylated in the liver to calcidiol and then to the active metabolite calcitriol (1a,25-dihydroxycholecalciferol) in the kidney. Calcitriol is the most active metabolite of Vitamin D, and specific receptors are found in the kidney, intestine, and bone [18] . Its primary function is to increase active intestinal calcium absorption.

In younger individuals, vitamin D synthesis in the skin is the primary determinant of serum calcidiol levels; this cutaneous synthesis is reduced in elderly individuals. Elevations in serum parathyroid hormone (PTH) and greater bone loss are often associated with lower levels of calcidiol. Vitamin D insufficiency is believed to play a strong role in osteoporosis. The current US Dietary Reference Intake (DRI) from the National Academy of Sciences recommendation for vitamin D intake in persons aged 51 to 70 years is 10 µg per day (400 IU/day), and the recommended intake for those older than 70 years is 15 µg per day (600 IU/day; see Table 1 ). Higher doses of vitamin D (800–1000 IU/day) in elderly persons (age, = 65 years) may be required for optimal bone health. These higher vitamin D doses (in combination with calcium) have been shown to reduce fracture risk in this population. Rich natural sources of vitamin D include fatty fish, fish liver oils (eg, cod liver oil), and liver. Several foods are also fortified with vitamin D, including milk (eg, cow, soy, and rice milk), some yogurts, cereals, nutrition bars, and margarine.

Summary

The nutritional needs for optimizing bone health easily can be met by a diet that is high in fruits and vegetables (five or more servings/day), adequate in protein but moderate in animal protein, and with adequate calcium and vitamin D intakes through the consumption of low fat dairy or calcium-fortified foods. Foods are a preferred source to maintaining calcium balance because there are other essential nutrients that are found in high-calcium foods. For those individuals in whom there is inadequate calcium intake from diet, supplemental calcium can be used. Supplemental or dietary calcium should be spread out throughout the day, with 500 mg or less being consumed at each meal to optimize absorption.

In all individuals older than 70 years, vitamin D intakes of at least 600 IU per day (up to 1000 IU/day) are recommended, in addition to the calcium requirement of 1200 mg per day. Vitamin D from foods, supplements, and/or multivitamins can be used to meet the vitamin D requirement.

In frail elderly individuals with malabsorption and alcoholics, there may be a need to supplement magnesium. Some elderly individuals with indications of poor nutritional status (low albumin levels) or after hip fracture might benefit from protein supplementation and a multivitamin to ensure adequacy of other nutrients.

RE: [ ] Another Vitamin D Benefit

One more..>> I recall some suggestions as high as 4000 IU. Additionally, we also now realize that the Food and Nutrition Board's previouslydefined Upper Limit (UL) for safe intake at 2,000 IU/day was setfar too low and that the physiologic requirement for vitamin D inadults may be as high as 5,000 IU/day, which is less than half ofthe >10,000 IU that can be produced endogenously with full-bodysun exposure.1,21. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Am JClin Nutr. 1999;69(5):842-56.2. Heaney RP, Davies KM, Chen TC, Holick MF, Barger-Lux MJ. Human serum 25-hydroxycholecalciferolresponse to extended oral dosing with cholecalciferol. Am J Clin Nutr.2003;77(1):204-10.http://www.bioticsresearch.com/PDF/Vitamin%20D%20ATHM2004%20Vasquez.pdf