Researcher recommends vitamin D supplements for the elderly

FAPESP-funded studies coordinated by Marise Lazaretti Castro (Unifesp) reveal that the incidence of vitamin deficiency in the population of São Paulo is high, especially among older individuals.

By Karina Toledo

Agência FAPESP – The incidence of vitamin D deficiency in major urban centers such as São Paulo has reached alarming levels, especially among the elderly, warns doctor Marise Lazaretti Castro, professor of Endocrinology at Universidade Federal de São Paulo (Unifesp). Castro is the head of the Osteometabolic Disease department at the Paulista School of Medicine. He has studied vitamin D deficiency for more than 15 years.

The main culprit is not poor eating habits but rather a lack of sun exposure. The majority of this nutrient is synthesized inside the skin upon stimulation from ultraviolet rays. This process is hampered by the use of sunscreen.

“Normally, 20 minutes of sun exposure in the early morning or late afternoon is sufficient, but this is not necessarily always true. It is difficult to know with certainty how much sun is necessary. Black people need more time in the sun than white people, and the elderly need at least three times that time to produce the same quantity of vitamins as young people,” said Castro.

Modern living does not lend itself to sunbathing. To adapt to this new reality, vitamin supplements are a must.

Castro says that vitamin D supplements should be part of routine geriatric treatment and mandatory for groups at risk of bone fracture, such as elderly persons living in institutions, lupus patients, osteoporosis patients and post-menopausal women. Excerpts from Agência FAPESP’s interview with the researcher are below:

Agência FAPESP – Is it possible for the population of a country as sunny as Brazil to suffer from vitamin D deficiency?
Marise Lazaretti Castro – Vitamin D deficiency in the Brazilian population is widespread, especially among the institutionalized elderly. In a study conducted in São Paulo, we showed that 92% of the 177 institutionalized elderly people that we evaluated had insufficient vitamin D levels. In 243 elderly individuals who lived at home, this figure was 85%. Among the young volunteers that composed our control group, the rate was 40%. When we evaluate the percentages of people with vitamin D deficiency, that is, with values further below the ideal, the institutionalized elderly accounted for 40%, elderly living at home represented 15% and young people made up the other 15%. That study was concluded in 2004. Later studies indicated that although the numbers for vitamin deficiency among the institutionalized elderly are frightening, these individuals are still not receiving supplements, likely because doctors do not remember to give them. There are significant national data that confirm our findings regarding the prevalence of vitamin D deficiency in other populations. Cases of vitamin D insufficiency have been found from Recife [Northern Brazil] to Porto Alegre (Southern Brazil].

Agência FAPESP – What characterizes vitamin D insufficiency and deficiency, and what are the consequences of each?
Castro – The most conservative recommendation is that normal levels be defined 20 nanograms (ng) of 25-hydroxyvitamin D (25(OH)D)—which is the metabolic dose in the test—per milliliter (ml) of blood. Our results, however, follow the American Endocrinology Society standards, which recommend levels above 30 ng/ml. Values below 10 ng/ml are defined as deficiency. Values between 10 and 30 ng/ml are considered to indicate insufficiency, which is associated with an increased risk of osteoporotic fracture because it stimulates an elevation of the production of parathyroid hormones (PTH), which provokes bone demineralization. This phenomenon is known as secondary hyperparathyroidism caused by vitamin D insufficiency. Cases of deficiency cause a more serious illness: osteomalacia, or the softening of the bones. Deficiency also causes broad muscular weakness. Recent studies have associated vitamin D deficiency with a series of other health problems, such as breast cancer, prostate cancer, and colorectal cancer, in addition to autoimmune conditions such as diabetes and multiple sclerosis.

Agência FAPESP – What are the causes of hypovitaminosis in the Brazilian population?
Castro – The causes are lack of sun exposure and the use of sunscreen. When doctors recommend that their patients use sunscreen and avoid sunlight in peak hours, they should also prescribe vitamin D supplements. They say that 20 minutes of sun exposure in the early morning or late afternoon are enough, but this is not necessarily true. It is hard to know exactly how much sun is needed. Black people need more time in the sun than white people, and the elderly take at least three times longer to produce the same quantity of vitamins as younger individuals. Furthermore, an erythematic dose of ultraviolet rays, that is, an amount of sun that leaves the skin red, is necessary to stimulate the production of vitamin D. The data in our study suggest that serum levels of vitamin D are very much linked to sun exposure and that there is seasonal variation in vitamin D levels. The levels were highest in the months following summer, i.e., autumn. After winter, the levels were lowest. In young people, this decrease is almost 50%.

Agência FAPESP – Does diet have an influence?
Castro – Diet is practically irrelevant. Recent studies have shown that the average daily dietary intake is below 100 units of vitamin D per day. There are a few foods with significant quantities of vitamin D, but they are not consumed very frequently—they include fatty fish such as tuna, salmon and mackerel. Now, there are also vitamin-enriched foods such as yogurt and milk. This could help improve intake, but I don’t think these foods provide the ideal quantity.

Agência FAPESP – What is the ideal intake?
Castro – We normally base our recommendations on the findings of U.S. health agencies. In their latest revision, they increased the ideal intake to 600 units daily, but I think this value is still low, particularly for groups at risk of bone fracture. A study conducted in patients at the Unifesp Osteoporosis Clinic in the Endocrinology Ward—mostly post-menopausal women—found that the ingestion of 2,000 units daily would be necessary to maintain ideal levels. The study also showed that patients who exercised regularly had higher levels of vitamin D.

Agência FAPESP – How does physical activity help?
Castro – We still don’t know for sure, but it is certainly a topic that must be investigated in future research. The fact that exercising outdoors is related to a greater chance of sun exposure may be a factor, and the half-life of vitamin D may also be increased in situations of greater metabolic energy expenditure because it is liposoluble.

Agência FAPESP – Which groups need greater attention and supplementation?
Castro – Our work on seasonal variation showed that black people had lower values of vitamin D than whites. Men had much lower values than women did. Furthermore, vitamin D levels decreased with age.. The institutionalized elderly undoubtedly have the greatest risk of fractures, and vitamin D supplements should be part of their daily regimens. Another study showed that patients with systemic erythematous lupus, who are prohibited from sun exposure to prevent the progression of their disease, also have an increased risk of fracture.

Agência FAPESP – In your opinion, should supplements be part of the standard treatment for all elderly?
Castro – Yes. In our hospital, we prescribe vitamin D supplements for all patients. We realized after our last study that 1,000 units is still a low dose. Another research group showed that a simple vitamin D supplement could increase muscle force in elderly individuals with vitamin D deficiency. Forty-six patients were split between two groups. Half received supplements and the other received a placebo. In the group that received the supplement, hip flexor muscle strength increased by 16.4% relative to baseline levels, and the strength of the knee extensor muscles increased by 24.7%. Because these are the muscles that are involved in walking, this increase in strength reduces the risk of falls.

Agência FAPESP – Are there any risks associated with supplements?
Castro – No, not at the dosage that we are recommending, which is 2,000 units per day. To induce toxicity, a person would have to consume more than 10,000 units per day over 6 months. I have seen a few cases of vitamin intoxication in my life, and all were errors of formulation. The problem is that there are few pure presentations of vitamin D in pharmacies. The majority of formulas include vitamin A or calcium or are multivitamins. To reach the ideal vitamin D values [with these formulas], individuals may be exposed to excess vitamin A, for example. Many patients buy formulas in compounding pharmacies, but there is not adequate quality control. The vitamin is unstable, and if the raw material is poor, it may not work. More varieties of processed medicines that offer guaranteed stability, safety and efficacy are needed. Government laboratories could manufacture them at a much lower cost, greatly benefitting the population. We must demand that vitamin D be included in the list of medicines that the unified health system utilizes because, at the moment, it is not provided.

Agência FAPESP – What are the main benefits of supplements?
Castro – The main benefit is certainly a reduced risk of fracture, especially among the elderly. In the most serious cases of deficiency, supplementation would help improve muscle strength. Many other benefits have been associated with the use of vitamin D, such as reduced cancer risk, improved immunological response to infections and reduced risk of autoimmune disease. Yet doctors are still afraid to prescribe the vitamin. The culture must be changed to adapt to current lifestyles. We do not work outdoors, we use sunscreen, we don’t often walk places and we still have not adapted to this reality.

The article Treatment of Vitamin D Deficiency Increases Lower Limb Muscle Strength in Institutionalized Older People Independently of Regular Physical Activity: A Randomized Double-Blind Controlled Trial (doi: 10.1159/000235874) can be read at content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ArtikelNr=235874&Ausgabe=250369&ProduktNr=223977&filename=235874.pdf.

The article Increases in summer serum 25-hydroxyvitamin D (25OHD) concentrations in elderly subjects in São Paulo, Brazil vary with age, gender and ethnicity (doi:10.1186/1472-6823-10-12) can be read at www.biomedcentral.com/1472-6823/10/12.

The article Prevalência da Deficiência, Insuficiência de Vitamina D e Hiperparatiroidismo Secundário em Idosos Institucionalizados e Moradores na Comunidade da Cidade de São Paulo, Brasil (doi: 10.1590/S0004-27302007000300012 ) can be read at www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-27302007000300012&lng=en&nrm=iso.

The article Vitamin D deficiency in patients with active systemic lupus erythematosus (doi: 10.1007/s00198-008-0676-1) can be read at link.springer.com/article/10.1007%2Fs00198-008-0676-1.

The article The effect of sun exposure on 25-hydroxyvitamin D concentrations in young healthy subjects living in the city of São Paulo, Brazil (doi: 10.1590/S0100-879X2006005000162 ) can be read at www.scielo.br/scielo.php?pid=S0100-879X2007001200009&script=sci_arttext.