Long-term effect of calcium-vitamin D3 fortified milk on blood pressure and serum lipid concentrations in healthy older men

Abstract

Background/Objectives: Some epidemiological and clinical studies have shown that increased dairy consumption or calcium and/or vitamin D supplementation can have a beneficial effect on blood pressure, and lipid and lipoprotein concentrations. The aim of this study was to assess the long-term effects of calcium-vitamin D 3 fortified milk on blood pressure and lipid-lipoprotein concentrations in community-dwelling older men. Subjects/Methods: This is a substudy of a 2-year randomized controlled trial in which 167 men aged 450 years were assigned to receive either 400 ml per day of reduced fat (B1%) milk fortified with approximately 1000 mg of calcium and 800 IU of vitamin D 3 or to a control group receiving no additional fortified milk. Weight, blood pressure, lipid and lipoprotein concentrations were measured every 6 months. Participants on lipid-lowering (n ¼ 32) or antihypertensive medication (n ¼ 39) were included, but those who commenced, increased or decreased their medication throughout the intervention were excluded (n ¼ 27). Results: In the 140 men included in this study (milk, n ¼ 73; control, n ¼ 67), there were no significant effects of the calciumvitamin D 3 fortified milk on weight, systolic or diastolic blood pressure, total cholesterol, high-density lipoprotein or low-density lipoprotein cholesterol or triglyceride concentrations at any time throughout the intervention. Similar results were observed after excluding men taking antihypertensive or lipid-lowering medication or limiting the analysis to those with baseline calcium intakes o1000 mg per day and/or with hypovitaminosis D (25(OH)D o75 nmol/l). Conclusions: Supplementation with reduced-fat calcium-vitamin D 3 fortified milk did not have a beneficial (nor detrimental) effect on blood pressure, lipid or lipoprotein concentrations in healthy community-dwelling older men.

Long-Term High-Dose Vitamin D 3 Supplementation and Blood Pressure in Healthy Adults

“…The isolated decrease in systolic BP among the vitamin D group at 5 months' follow-up is most likely a chance finding, because this small difference was not observed at 18 months (Table 3), although we cannot rule out a short-term true effect over several months during winter when the 25(OH)D 3 difference (74 nmol/L) between comparison groups was highest (Table 2). These results confirm previous studies of long-term supplementation (≥1 year), which have reported either no effect of vitamin D supplementation on BP 14,15,[28][29][30][31][32] or an increase in systolic BP in participants given 20 000 IU per week. 32 We think the latter is probably a chance finding because there was no change in systolic BP among participants given 40 000 IU per week.…”

“…However, previous studies have failed to detect a differential effect of vitamin D on either BP measure. 13,15 All previous long-term supplementation studies, 14,15,[28][29][30][31][32] including our own, have enrolled mainly participants of European ancestry (ie, white race). It is possible that vitamin D could lower BP in other specific race/ethnic groups, as observed in an Iranian study that supplemented with fortified yoghurt for 12 weeks 23 and in a recent study of blacks supplemented for 3 months.…”

“…decrease <5 mm Hg) that would be of biological (if not clinical) significance. 15,28,30,31 Given these limitations, we decided to study the effect of long-term (18 months) high-dose vitamin D supplementation on BP. The present study was a prespecified secondary aim in a double-blind randomized controlled trial where the primary objective was to determine if vitamin D prevents upper respiratory tract infections.…”

The Impact of Vitamin D on Weight Loss

“…23,24 However, there was also a greater reduction in energy intake in cereal diet that was due to a ~1,000 kJ greater initial intake, which may also have contributed to the greater weight loss. 23 While vitamin D intake was increased, it was still suboptimal and the differences were seen over a short time-frame of only 26,27 One study found no differences in weight changes between the groups, 26 and the other found weight significantly increased by 1.0 kg in the milk group compared with the nonmilk group and there was a trend for a greater increase in fat mass of 0.6 kg. 27 The milk group in the second study also significantly increased their energy compared with no change in the other groups (+846 kJ/day), which could have impacted on the weight gain.…”

“…28 25OHD levels were not measured, so they were not able to determine if the fortified products improved vitamin D status or if it was other parts of the intervention that were having the beneficial impact. In the majority of these studies the participants were vitamin D sufficient at baseline [25][26][27] that, along with the low dose of vitamin D in the fortified products, could also have accounted for a modest increase in 25OHD levels. In some studies the products led to differences in energy intake that could have influenced subsequent weight loss and the products fortified with vitamin D and calcium.…”