At the ESCIM congress in Geneva, Prof. Dr. med Reto W. Kressig from the University Center for Geriatric Medicine, Felix-Platter-Spital, Basel, presented the debate that has been going on for years on the subject of calcium and vitamin D supplementation and the current state of knowledge on the benefits and risks.
Adequate calcium and vitamin D intake is important for healthy bone, but supplementation is controversial. Without wanting to add fuel to the fire, Prof. Reto W. Kressig, MD, of the University Center for Geriatric Medicine, Felix Platter Hospital, Basel, asked, “What are the facts?”
In 2010, the Institute of Medicine (IOM) in the USA published a statement on the subject of what constitutes sufficient coverage of the daily requirement of calcium and vitamin D. The statement is based on the following values The values were 1200 mg calcium and 400-600 IU vitamin D. However, Europe and Switzerland have since distanced themselves from these target values. The German-speaking nutrition societies have limited the maximum recommended calcium intake to 1000 mg per day. These values have been created with regard to risks and complications of high calcium intake. On the one hand, the incidence of milk-alkali syndrome, which had already fallen into oblivion, had increased. In particular, the simultaneous use of antacids containing bicarbonates leads to increased nausea and vomiting as well as increased stone formation.
On the other hand, it is now known from several studies that calcium substitution without simultaneous vitamin D administration is not only of no use, but actually increases the risk of hip fracture. A well-received study had shown that supplementation of more than 500 mg of calcium daily without concomitant vitamin D supplementation increased the risk of myocardial infarction [1]. The average amount of dietary calcium consumed in adulthood is 700 mg for women and 800 mg for men, Kressig said. “That’s where we’re not too far from the recommended levels.” The calcium calculator at www.rheumaliga.ch can be used to understand a patient’s individual calcium intake when discussing supplementation, he said. If calcium administration is necessary, 500 mg in combination with vitamin D is on the safe side.
Caution with calcium
In the primary prevention of fractures in healthy postmenopausal patients, supplementation with calcium and vitamin D is now discouraged [2]. A very low calcium intake of less than 800 mg per day is associated with an increased risk of hip fracture; however, an intake of more than 800 mg daily does not appear to confer any benefit [3]. The intake of this dose is normally ensured through food. Calcium intake above 1000 mg daily is also suspected to increase cardiovascular risk. Patients with proven vitamin D deficiency, on the other hand, benefit from calcium supplementation.
Vitamin D is important in old age
Less than 20% of the population in Europe has adequate vitamin D levels, and in the U.S. about two-thirds are below the target level. That makes it all the more surprising that, according to the IOM, vitamin D supply is not a problem in the U.S., Kressig said. Vitamin D is essential for cognitive and immunological processes, especially in old age. To cover the daily requirement (800 IU according to the latest guidelines) from food, about two portions of fatty fish per day are needed, which is not achieved in Switzerland. Exposure of the whole body to the sun for 20 minutes brings about 14 000 IU. However, it should be borne in mind that vitamin D synthesis in the skin is already completely suppressed with a sun protection factor of 8, says Kressig. In addition, old patients in particular need four times longer periods of sun exposure than younger people due to skin aging. It can therefore be assumed that many people in Switzerland also live with a latent vitamin D deficit.
A much higher level than previously thought, namely a 25-hydroxyvitamin D level of 75 nmol/l, is probably optimal for fall and fracture prevention, Kressig said. We know from bone health intervention studies that vitamin D prevents falls and fractures in a dose-dependent manner. In the prevention of nonvertebral fractures, supplementation with vitamin D has been shown to be protective, independent of concomitant calcium supplementation.
Avoid Alzheimer’s and Parkinson’s disease?
“Vitamin D plays a role not only in muscles and bones, but also in cognition,” the expert reported. So far, however, there are only epidemiological studies, for example on the correlation of cognitive functions (“Mini Mental Scale”, MMS) with vitamin D levels. “The higher the vitamin D level, the less cognitive impairment in patients with Alzheimer’s disease,” the geriatrician said. Low serum levels are also associated with an increased risk of Parkinson’s disease. A threshold of 50 nmol/l (20 ng/ml) appears to correlate with cognitive impairment in the elderly [4].
Avoid overdose
That an oral mega-dose of 500,000 IU vitamin D once a year is also not an alternative was shown by a study [5] in which there was an increased incidence of falls and fractures, particularly in the first few months after administration. The Federal Office of Public Health recommends substitution with 800 IU per day for patients 60 years of age and older, and 1500-2000 IU for proven deficiency. However, a maximum dose of 4000 IU daily should not be exceeded.
Source: Presentation at the European and Swiss Congress of Internal Medicine (ESCIM), May 14-16, 2014, Geneva.
Literature:
- Bolland MJ, et al: Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ 2010 Jul 29; 341: c3691.
- Moyer VA, et al: Vitamin D and calcium supplementation to prevent fractures in adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2013; 158(9): 691-696.
- Warensjö E, et al: Dietary calcium intake and risk of fracture and osteoporosis: prospective longitudinal cohort study. BMJ 2011 May 24; 342: d1473.
- Llewellyn DJ, et al: Vitamin D and Cognitive Impairment in the Elderly U.S. Population. J Gerontol A Biol Sci Med Sci Jan 2011; 66A(1): 59-65.
- Sanders KM, et al: Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial. JAMA 2010; 303(18): 1815-1822.
HAUSARZT PRAXIS 2014; 9(7): 40-41
CONGRESS SPECIAL 2014; 23-24
