Biomedical subjects

David B Milne

Publications and source records attributed to David B Milne.

3 recordsLinked to original sources

PubMed2004

Zinc intakes and plasma concentrations in men with osteoporosis: the Rancho Bernardo Study.

BACKGROUND: Low zinc intakes and reduced blood zinc concentrations have been reported to be associated with osteoporosis in women. OBJECTIVE: The objective was to examine the independent association between dietary zinc and plasma zinc and the association of each with bone mineral density (BMD) and 4-y bone loss in community-dwelling older men. DESIGN: Of the original Rancho Bernardo Study subjects, 396 men (age: 45-92 y) completed BMD measurements at baseline in 1988-1992 and 4 y later. Osteoporosis was defined as a BMD > or = 2.5 SDs below the mean for young women (a T-score < or = -2.5). At baseline, dietary intake data were collected by using a standard food-frequency questionnaire, and plasma zinc concentrations were measured by using inductively coupled plasma spectroscopy. RESULTS: The mean dietary zinc intake was 11.2 mg, and the mean plasma zinc concentration was 12.7 micromol/L. Plasma zinc was correlated with total zinc intake (diet plus supplements). Dietary zinc intake and plasma zinc concentrations were lower in men with osteoporosis at the hip and spine than in men without osteoporosis at those locations. BMDs for the hip, spine, and distal wrist were significantly lower in men in the lowest plasma zinc quartile (<11.3 micromol/L) than in men with higher plasma zinc concentrations. The association between plasma zinc and BMD was cross-sectional, longitudinal, and independent of age or body mass index. However, plasma zinc did not predict bone loss during the 4-y interval. CONCLUSION: Dietary zinc intake and plasma zinc each have a positive association with BMD in men.

Absorptiometry, Photon↗

PubMed2002

Low dietary magnesium increases supraventricular ectopy.

BACKGROUND: Magnesium has been suggested to be beneficial in counteracting all phases of the processes that lead to ischemic heart disease, including terminal events such as arrhythmia and sudden death. OBJECTIVE: We tested the hypothesis that an intake of magnesium considerably below the recommended dietary allowance can produce chemical and physiologic evidence of depletion. DESIGN: Twenty-two postmenopausal women were maintained in a metabolic unit and ate a diet of conventional foods containing less than one-half of or more than the recommended dietary allowance for magnesium (320 mg/d). Dietary assignments were random and double blind in a crossover design. Magnesium concentrations were measured by spectroscopy and ion-specific electrolyte analysis, and Holter electrocardiograms lasting approximate 21 h were recorded. RESULTS: Magnesium concentrations in erythrocytes, serum (total and ultrafilterable), and urine were significantly lower when dietary magnesium was lower. Holter monitors showed a significant increase in both supraventricular and supraventricular plus ventricular beats when the dietary magnesium concentration was low. Hypomagnesemia, hypocalcemia, and hypokalemia were not found. CONCLUSIONS: The magnesium requirement was defined with the use of biochemical and electrophysiologic criteria. The recommended dietary allowance of 320 mg/d seems correct; 130 mg is too little. Persons who live in soft water areas, who use diuretics, or who are predisposed to magnesium loss or ectopic beats may require more dietary magnesium than would others.

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PubMedDate not supplied

Some magnesium status indicators and oxidative metabolism responses to low-dietary magnesium are affected by dietary copper in postmenopausal women.

OBJECTIVE: A study with human volunteers was conducted to ascertain whether a low intake of copper (Cu) would exacerbate the response to a deficient intake of magnesium (Mg). METHODS: Nineteen postmenopausal women, age 47 to 78 y, completed a metabolic unit study as designed. For 162 d, nine women were fed a diet containing 1.0 mg of Cu/2000 kcal and 10 women were fed 3.0 mg of Cu/2000 kcal. Diets contained 99 or 399 mg of Mg/2000 kcal for 81 d in a randomized, double-blind, crossover design. Differences were considered significant when statistical analysis yielded P </= 0.05. RESULTS: Magnesium balance was highly positive when the dietary magnesium was high but non-positive when dietary magnesium was low. Copper balance was more positive when dietary copper was high than when it was low. Plasma ionized magnesium was decreased by magnesium deprivation. Several variables measured indicated that low dietary copper affected the response to magnesium deprivation or vice-versa. Red blood cell magnesium was lower when dietary copper was low than when it was high. When dietary magnesium was low, serum copper was lower in the women fed marginal copper than in those fed luxuriant copper. When dietary magnesium was high, low dietary copper did not affect serum copper. Magnesium deprivation decreased red blood cell superoxide dismutase when dietary copper was luxuriant; when dietary copper was low, magnesium deprivation did not have much of an effect. Apolipoprotein A1 was lowest when dietary magnesium and copper were low. The order in which the magnesium restriction occurred affected the response of a number of variables to this treatment including concentrations of serum magnesium and total and low-density lipoprotein cholesterol. CONCLUSIONS: The findings indicated that, in short-term magnesium depletion experiments, the response to depletion can be influenced by other dietary factors including copper intake and a high magnesium intake before depletion, and that 100 mg of Mg/d is inadequate for postmenopausal women.

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