High or Low Calcium Intake Increases Cardiovascular Disease Risks in Older Patients With Type 2 Diabetes

Jui-Hua Huang; Leih-Ching Tsai; Yu-Chen Chang; Fu-Chou Cheng

Disclosures

Cardiovasc Diabetol. 2014;13(120) 

In This Article

Background

Diabetes is frequently associated with cardiovascular disease (CVD) and cardiovascular complications.[1] In general, patients with diabetes have high risk for CVD, a major death factor, particularly in older patients.[2,3] Inflammation also plays a key role in the pathogenesis and progression of CVD in patients with diabetes.[4–6] Diet, lifestyle, and medical interventions may promote or retard inflammatory responses in diabetic management.[7–9] Low magnesium (Mg) and calcium (Ca) intakes raise inflammatory and CVD risks.[10–12] However, the effects of high Ca or Mg intakes on cardiovascular risks in patients with diabetes remain unclear.

Low Mg intakes are associated with increased inflammation and risk of type 2 diabetes and CVD.[12–14] A nationally representative cross-sectional survey showed that adults in the USA consuming Mg below the recommended dietary allowances (RDAs) were more likely to have elevated C-reactive protein (CRP), which may contribute to CVD risks.[12] In rodents, the intake of an Mg-deficient high-fat diet led to alterations in the insulin-signaling pathway and increased insulin resistance.[15] In patients with diabetes, low serum Mg levels were found to be associated with macrovascular complication,[16] and hypomagnesemia was arryhtmogenic.[17] In addition, low serum Mg levels increased chronic inflammatory stress that could be alleviated by increasing Mg intakes in middle-aged people with poor quality of sleep.[18] Dietary Ca intakes were also reported to be associated with the modulation of inflammatory stress and pathogenesis of CVD.[11,19,20] However, whether high Ca intake decreases or increases the risk of CVD remains controversial.[11,20] Zemel et al.[19] found that dietary Ca suppresses oxidative and inflammatory stress. A cross-sectional study showed that increased Ca intakes decreased the risk of several CVD risk factors.[21] In contrast, in another study, increasing dietary Ca intake or use of Ca supplementation was noted to raise myocardial infarction risks.[22] Although Mg and Ca intakes are closely related to inflammation and CVD risks, they also interact and each antagonizes the other's absorption in the intestinal tract.[23] Mg is a natural physiologic Ca antagonist. Therefore, varied Mg and Ca dietary intakes can alter the absorption of Mg or Ca alone, and inappropriate Mg and Ca dietary intakes can cause additional CVD risks.

The intestinal absorption of Ca or Mg may depend on the amounts of Ca and Mg present in the diet.[23] Therefore, owing to the nature of these intestinal interactions, the dietary Ca:Mg intake ratio and the absolute amount of Ca or Mg in the daily diet may be equally important in reducing CVD risks. Recently, Dai et al. found that the impact of Ca:Mg intake ratio on the risk of CVD had significantly higher modifying effects than that of Ca or Mg intake alone in Chinese populations.[24] In addition, the United States Department of Agriculture (USDA) food surveys from 1977 through 2008 showed a rise in the Ca:Mg intake ratio, which coincided with the increased prevalence and incidence of type 2 diabetes.[25] Therefore, the effects of dietary Ca and Mg intakes on CVD risks may vary depending on the dietary Ca:Mg intake ratio. Thus, the roles of dietary Ca and Mg intakes and their ratio in the prevention of CVD warrant further investigation.

Older patients with diabetes are at high risk for CVD,[2,3] and Mg deficiency is common in this population.[26,27] Mg deficiency may be exacerbated by low Mg with high or low Ca intakes,[13,28] which may trigger inflammatory stress, contributing to the development of CVD.[13] However, the effects of dietary Ca and Mg intakes on CVD risk have not been intensively explored in older patients with diabetes. To date, numerous studies have demonstrated correlations between Ca or Mg intakes alone with CVD risk,[10,29,30] but relatively few studies have examined the potentially combined effects of dietary intakes of Ca and Mg on CVD risk.[24] The present study was conducted to explore CVD risks in older patients with type 2 diabetes with respect to their dietary Mg and Ca intakes and Ca:Mg intake ratios. Dietary intakes and lifestyle data were obtained and assessed using questionnaires. In addition, anthropometric measurements were determined and biochemical analysis of blood and urine samples was performed.

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