The importance of maintaining optimal vitamin D levels after menopause

The decrease in female sex hormones causes fragility and loss of bone mass, which increases the risk of developing osteoporosis and fractures, a common occurrence in women over 50 years of age. However, let’s look at how we can minimize this impact on women’s bone health.

Dr. César Montiel – Neolife Medical Team

Menopause is a vulnerable stage, from a nutritional point of view, because energy expenditure decreases (due to changes in body composition and decreased activity), while the needs for some nutrients such as vitamin D increase (1, 2). Loss of ovarian function has a profound impact on female bone health. The decrease in bone mineral density accelerates in the year prior to the last menstrual period and in the following two years (5). Although the etiology of osteoporosis is multifactorial, vitamin D intake, from the diet and from supplements, appears to have a key impact on the maintenance of bone mineral density, prevention of fractures and falls (3-4).

Vitamin D plays a central role in calcium metabolism, so adequate intake, either through the diet or by cutaneous synthesis in response to sunlight, is essential for lifelong health. Parathyroid hormone or parathormone (PTH) regulates the production of 1,25 dihydroxyvitamin D and the formation of the active form of vitamin D necessary for calcium homeostasis. Chronic vitamin D deficiency leads to secondary hyperparathyroidism with higher bone turnover, progressive bone loss, and higher risk of fracture due fragile bones (5, 6).

The prevalence of vitamin D deficiency in the general population and especially in post-menopausal women is significant and is currently considered an important public health problem. This deficiency may have key consequences not only for bone health, but may possibly play a role in autoimmune, neoplastic, infectious, and cardiovascular diseases (6-7).

From a metabolic point of view, modern life has supposed for women, an increase in the prevalence of diseases such as obesity, insulin resistance, and diabetes, mediated by an increase in the amount of visceral fat. High-calorie diets, sedentary lifestyles, and all the unhealthy lifestyle habits of our urban life have contributed to this increase in pathologies that in the long run dramatically increase the risk of suffering a cardiovascular event.

In urban areas, 50% of women over 50 years of age suffer from this metabolic syndrome. This means that half of all women suffer from excess visceral fat at the abdominal level.

Moreover, vitamin D deficiency is considered to be the most frequent medical problem worldwide, intensifying after menopause (65% of postmenopausal women have severe vitamin D deficiencies).

Recent studies (1, 2) link vitamin D deficiency to the appearance of chronic diseases like high blood pressure and type 2 diabetes, which exponentially increase patients’ vascular risk. On the opposite side of the spectrum, patients with high vitamin D levels have a rate of cardiovascular events that is up to 51% lower than the normal population’s.

A meta-analysis of more than 210,000 patients confirms a 20% higher risk of these cardiometabolic pathologies.

In January 2018, the journal Maturitas published a cohort study of 463 postmenopausal women, showing that those with low vitamin D levels had a higher risk of metabolic syndrome, hypertriglyceridemia, and low HDL cholesterol (good cholesterol) levels, and that this risk was higher than in the population with low vitamin D levels, i.e., in postmenopausal women the effect of low vitamin D levels was more acute.

These results are consistent with the conclusions obtained in previous research (3, 4), and even in the WHI, in 2002, a possible link between low vitamin D levels and the occurrence of cardiovascular events was already mentioned.
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In these studies, in general, it is observed in a linear and exponential manner that, as vitamin D levels decrease, the risk of the previously mentioned vascular risk factors increases independently.

There are multiple pathophysiological mechanisms that may explain this association. The most logical, and also the most scientifically based, is that vitamin D has a crucial influence both on insulin secretion by the beta cells of the pancreatic islets of Langerhans and on insulin sensitivity by receptors located in skeletal muscle cells and adipocytes. When the concentration of vitamin D decreases, these mechanisms are altered, leading to a lower production of insulin with greater resistance to its action in the periphery, which is what triggers the metabolic syndrome.

Vitamin D deficiency affects the ability of the pancreatic beta cell to convert pro-insulin to insulin. With respect to insulin sensitivity, vitamin D regulates calcium levels in the extracellular space of both skeletal muscle fiber and adipocytes, which facilitates insulin action at that level. Vitamin D deficiency increases resistance to insulin action.

In these studies, levels below 30ng/ml are considered vitamin D deficiency, and levels below 20ng/ml are considered severe deficiency. Levels above 30ng/ml are considered sufficient; however, numerous publications demonstrate the need to reach vitamin D concentrations of around 50-60ng/ml, to prevent the possibility of suffering any of the consequences of vitamin D deficiency.

At Neolife, as with the rest of the biomarkers we study in our patients, we treat our patients to achieve vitamin D levels in a range of excellence that decreases the possibility of the onset of metabolic diseases, thus preventing the possibility of cardiovascular events. Additionally, with a proper diet, regular physical exercise, and the necessary daily amount of calcium and vitamin D, we can minimize the impact of estrogen depletion on women’s bone health after menopause.

BIBLIOGRAPHY

(1) Navia B, Ortega RM. Ingestas recomendadas de energía y nutrientes [Recommended energy and nutrient intakes]. In: Nutriguía. Manual de  Nutrición Clínica en Atención Primaria. Chapter 1. Requejo AM, Ortega RM eds. Madrid: Editorial Complutense. 2006; 3-14.

(2) Riobó P. Mujer adulta y menopausia [The adult woman and menopause]. In: Nutrición en población femenina: Desde la infancia a la edad avanzada. Ortega RM, ed. Madrid: Ediciones Ergón. 2007; 93-100.       

(3) Lowe NM, Ellahi B, Bano Q, Bangash SA, Mitra SR, Zaman M. Dietary calcium intake, vitamin D status, and bone health in postmenopausal women in rural Pakistan. J Health Popul Nutr 2011; 29 (5): 465-70.

(4) Boucher BJ. The problems of vitamin d insufficiency in older people. Aging Dis. 2012; 3(4): 313- 29.

(5) Melton LJ, Chrischilles EA, Cooper C, Lane AW, Riggs BL. Perspective. How many women have osteoporosis? J Bone Miner Res. 1992; 7:1005–10.

(6) Lips P, Hosking D, Lippuner K, Norquist JM, Wehren L, Maalouf G, et al. The prevalence of vitamin D inadequacy amongst women with osteoporosis: an international epidemiological investigation. J ntern Med. 2006; 260(3):245-54.

(7) Ahmadieh H, Arabi A. Vitamins and bone health: beyond calcium and vitamin D. Nutr Rev 2011; 69 (10): 584-98.