Higher Magnesium Intake Research Articles

Estimation of mineral and trace element intake in vegans living in Japan by chemical analysis of duplicate diets

Thirty-six daily duplicate diet samples were collected from 12 healthy female Japanese vegans and sodium, potassium, calcium, magnesium, phosphorus, iron, zinc, copper, manganese, iodine, selenium, chromium and molybdenum in the diets were measured to estimate mineral and trace element intake by Japanese vegans. Significantly higher intake of potassium, magnesium, phosphorus, iron, copper, manganese and molybdenum was observed in vegans than in general Japanese women, but no difference was observed in sodium, iodine, selenium and chromium intake. Vegan calcium intake tended to be low compared to that of general women but the difference was not significant. Since high potassium, magnesium and iron intakes cannot be achieved by general Japanese diets and high intake of potassium and magnesium may prevent hyperextension and cardiovascular disease in vegans, there are few problems with Japanese vegan diets regarding mineral and trace element intake, except for calcium intake, which is low as it is in the general Japanese people.

High Magnesium Intake Effects On Female Athlete'S Metabolism After High Intensity Exercise

High Magnesium Intake Effects On Female Athlete'S Metabolism After High Intensity Exercise

Dietary Calcium and Magnesium Intake and Mortality: A Prospective Study of Men

The authors examined the association of dietary calcium and magnesium intake with all-cause, cardiovascular disease (CVD), and cancer mortality among 23,366 Swedish men, aged 45-79 years, who did not use dietary supplements. Cox proportional hazards regression models were used to estimate the multivariate hazard ratios and 95% confidence intervals of mortality. From baseline 1998 through December 2007, 2,358 deaths from all causes were recorded in the Swedish population registry; through December 2006, 819 CVD and 738 cancer deaths were recorded in the Swedish cause-of-death registry. Dietary calcium was associated with a statistically significant lower rate of all-cause mortality (hazard ratio (HR) = 0.75, 95% confidence interval (CI): 0.63, 0.88; P(trend) < 0.001) and a nonsignificantly lower rate of CVD (HR = 0.77, 95% CI: 0.58, 1.01; P(trend) = 0.064) but not cancer mortality (HR = 0.87, 95% CI: 0.65, 1.17; P(trend) = 0.362) when the highest intake tertile (mean = 1,953 mg/day; standard deviation (SD), 334) was compared with the lowest (990 mg/day; SD, 187). Dietary magnesium intake (means of tertiles ranged from 387 mg/day (SD, 31) to 523 mg/day (SD, 38) was not associated with all-cause, CVD, or cancer mortality. This population-based, prospective study of men with relatively high intakes of dietary calcium and magnesium showed that intake of calcium above that recommended daily may reduce all-cause mortality.

Oral magnesium supplementation in adults with coronary heart disease or coronary heart disease risk

To review randomized control clinical trial (RCT) literature and prospective studies for the safety and efficacy of magnesium supplements in patients with coronary heart disease (CHD) or with CHD risk. Databases were searched using the keywords: magnesium, heart disease, endothelium, prevention, treatment, therapy, level, and supplement. There were no reports of adverse effects from magnesium supplementation in any of the studies. Subjects reporting lower dietary magnesium intake had significantly lower serum magnesium concentrations than those reporting higher dietary magnesium intake and, in some cases, had a significantly higher frequency of supraventricular beats. There was a modest relationship between dietary magnesium intake and a reduced risk of CHD in male subjects; however, there was no noted decrease in the development of CHD disease in women who had high magnesium intake. Magnesium is vital for many functions in the body and magnesium supplementation is safe. There is a possible association between a modestly lower risk of CHD in men and increased magnesium intake; therefore, it is reasonable to encourage diets high in magnesium as a potential means to lower the risk of CHD.

Ready-to-Eat Cereal Breakfasts Are Associated with Improved Nutrient Intake and Dietary Adequacy but Not Body Mass Index in Black Adolescents

The goal of this study was to determine whether nutrient intake, dietary adequacy, and weight status were associated with type of breakfast consumption: skipping breakfast, consuming ready-to-eat cereal (RTEC) at breakfast, or consuming other types of foods at breakfast. Data from black adolescents 13 to 18 years of age (n = 988) participating in the 1999-2002 National Health and Nutrition Examination Survey were used in a secondary data analysis. Thirty-seven percent of black adolescents skipped breakfast, 19% consumed RTEC at breakfast, and 44% consumed other breakfasts. RTEC breakfast and other breakfast consumers had higher mean energy intakes than breakfast skippers (P ≤ .05). After adjusting for gender and energy intake, RTEC breakfast consumers had higher intakes of thiamin, riboflavin, niacin, folate, calcium, phosphorus, magnesium, iron, zinc, potassium, and vitamins A, B6, and B12 than breakfast skippers and other breakfast consumers (P ≤ .05). RTEC breakfast consumers had the highest mean adequacy ratio, followed by other breakfast consumers, then breakfast skippers (P ≤ .05). Those consuming RTEC at breakfast had lower mean body mass index (P ≤ .05) and waist circumference (P ≤ .05) than breakfast skippers; however, there was no difference between those consuming RTEC and other breakfasts. If confirmed in prospective studies, consuming a breakfast meal with RTEC may be a useful strategy to encourage in black adolescents as a way to improve nutrient intake and dietary adequacy without increasing weight.

Comparison of effect of high intake of magnesium with high intake of phosphorus and potassium on urolithiasis in goats fed with cottonseed meal diet

The effect of high intake of Mg on urolithiasis was compared with high intake of P and K in goats being fed with a cottonseed meal and rice straw diet. Eighteen wether goats were randomly allocated into group A, B and C evenly and fed with cottonseed meal and rice straw diet for three months. From day 60 onwards, KH 2PO 4 and K 2HPO 4 were provided via drinking water to goats in group B to increase the intake of P, K, and MgO to goats in group C to increase the intake of Mg. Blood and urine samples were collected to analyze the concentration of P, K, Mg and Ca, and the activity product (AP) of potassium magnesium phosphate (MKP) in urine was also calculated. The composition of calculi and urinary sedimentary crystals were examined by chemical qualitative analysis, X-ray diffraction, X-ray energy dispersive spectrometry and Fourier transform infrared spectroscopy. The results showed that the incidence of urolithiasis in group C (6/6) was higher than that in group A (1/6) and B (1/6) ( P < 0.05). The calculi were mainly composed of magnesium ammonium phosphate (MAP) and partly composed of MKP. MKP presented in crystals of different phases in this experiment. The high intake of Mg contributed to a significant increase of plasma Mg, but additional P, K did not cause a further increase of plasma P, K. Urine P, K, Mg and Ca and AP of MKP in group C decreased significantly after the onset of urolithiasis. In conclusion, high intake of Mg was more important in inducing struvite calculi compared with high intake of K and P in goats under these feeding conditions. Cottonseed meal and rice straw with additional Mg is a good dietary model for inducing struvite calculi in castrated goats.

Abstract A62: Magnesium, calcium, and colorectal adenoma recurrence: Results from a randomized trial

Abstract A62 Background Mean magnesium intake in the US population is similar to that in East Asian populations with traditionally low risks of colorectal cancer and other chronic diseases, while the ratio of calcium to magnesium is much higher in the US population. It was recently reported that intakes of calcium or magnesium were associated with a reduced risk of adenoma or hyperplastic polyps only when dietary ratios of calcium to magnesium intake was low. Objective To test whether calcium supplementation reduces the risk of colorectal adenoma recurrence only when calcium/magnesium intake ratio is low. Design: The Calcium Polyp Prevention Study was a double-blind, placebo-controlled, randomized trial of 4 years of calcium supplementation (1000 mg) for the prevention of colorectal adenoma recurrence among 930 subjects. Participants underwent two follow-up colonoscopies, 1 year and 4 years after the qualifying exam. A validated semi-quantitative food frequency questionnaire was given at study entry and year 4 to obtain subjects’ usual diet over the previous year. The primary outcome in this analysis was the recurrence of adenomas during the main risk period (i.e. adenomas detected after the year 1 colonoscopy through the year 4 exam). This end point allowed for a latent period of calcium effect and minimized the number of adenomas overlooked at the qualifying colonoscopy. Results We found that dietary ratios of calcium to magnesium intake modified the effect of calcium treatment on adenoma recurrence (p for interaction: 0.075 for all adenoma and 0.046 for tubular adenoma during the main risk period). Calcium supplementation reduced the risk of adenoma recurrence only if the dietary ratio of calcium to magnesium intake was low before treatment and remained low during the treatment period. The RR (95%CI) was 0.68 (0.52-0.90) among those with the baseline ratio below the median in comparison to 0.98 (95%CI=0.75-1.28) for those above. Findings were similar when the intake ratio at year 4 was considered and when we repeated the analyses using adenomas detected during the full study period (e.g. including adenomas identified at year 1) and found very similar results. The sample size, however, became small when advanced adenomas were used as outcome; none of the associations were significant in the stratified analyses by calcium: magnesium ratio and the calcium effect did not differ substantially by ratio stratum (p for interaction, 0.575). We also found that high dietary intake of magnesium was related to a reduced risk of adenoma recurrence among subjects in the calcium treatment arm with a low ratio of calcium to magnesium intake; the RRs (95%CIs) for any adenoma were 0.66 (0.39-1.13) and 0.58 (0.32-1.06) for the intermediate and the highest intake tertiles vs. the lowest intake tertile of magnesium (p for trend, 0.054). There was no association observed in the placebo arm. Conclusions: We found that calcium supplementation reduced the risk of adenomas only among subjects with a low calcium:magnesium intake ratio. These findings, if confirmed, may provide a new avenue for the personalized prevention of colorectal cancer. The abstract is on behalf of the Polyp Prevention Study Group. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A62.

Hard drinking water does not protect against cardiovascular disease: new evidence from the British Regional Heart Study

It has been previously suggested that hard drinking water in general, and in particular high calcium and magnesium intake from drinking water, protect against cardiovascular disease. Prospective study of men from 24 British towns, with widely differing levels of hardness in drinking water. A total of 7,735 men aged 40-59 years were recruited during 1978-1980. Estimates of town-level water hardness were available and tap water samples, taken from 947 participants who also answered a questionnaire about water consumption, were used to calculate individual calcium and magnesium intakes. Men were followed for incident of major coronary heart disease (CHD) and stroke, and CHD mortality for 25 years. Water hardness varied from 0.27 to 5.28 mmol/l in the 24 towns. A weak inverse association was found between water hardness and incidence of cardiovascular disease (CVD) [hazard ratio (HR), 0.96 per two-fold increase, 95% confidence interval (CI), 0.91-1.01, P=0.08 after adjustment for age and seven established coronary risk factors]. No association was observed with CHD incidence (adjusted HR, 0.99, 95% CI, 0.94-1.04, P=0.62) or mortality (adjusted HR, 0.96, 95% CI, 0.90-1.02, P=0.18). Individual magnesium intake showed a positive, rather than an inverse, association with CHD incidence (adjusted HR, 1.10 per two-fold increase, 95% CI, 1.01-1.20, P=0.045); individual calcium intake was unrelated to CHD or CVD end points. This study suggests that neither high water hardness, nor high calcium or magnesium intake appreciably protect against CHD or CVD. Initiatives to add calcium and magnesium to desalinated water cannot be justified by these findings.

Magnesium, Calcium, Potassium, and Sodium Intakes and Risk of Stroke in Male Smokers

A high intake of magnesium, calcium, and potassium and a low intake of sodium have been hypothesized to reduce the risk of stroke. However, prospective data relating intake of these minerals to risk of stroke are inconsistent. We examined the relationship of dietary magnesium, calcium, potassium, and sodium intake with risk of stroke in a cohort of 26 556 Finnish male smokers, aged 50 to 69 years, who were free from stroke at baseline. Dietary intake was assessed at baseline using a detailed and validated food frequency questionnaire. During a mean follow-up of 13.6 years (1985-2004), 2702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were identified in the national registries. After adjustment for age and cardiovascular risk factors, a high magnesium intake was associated with a statistically significant lower risk of cerebral infarction but not with intracerebral or subarachnoid hemorrhages. The multivariate relative risk of cerebral infarction was 0.85 (95% confidence interval, 0.76-0.97; P for trend = .004) for men in the highest quintile of magnesium intake compared with those in the lowest quintile. The inverse association between magnesium intake and cerebral infarction was stronger in men younger than 60 years (relative risk, 0.76; 95% confidence interval, 0.64-0.89; P for interaction = .02). Calcium, potassium, and sodium intake was not significantly associated with risk of any subtype of stroke (P for trend > .05). These findings in male smokers suggest that a high magnesium intake may play a role in the primary prevention of cerebral infarction.

A higher magnesium intake is associated with a reduced risk of cholelithiasis,

A higher magnesium intake is associated with a reduced risk of cholelithiasis,

Effects of High Magnesium Intake on Bone Mineral Status and Lipid Metabolism in Rats

Effects of magnesium (Mg)-intake on mineral levels in bone, blood and various tissues, bone density and plasma lipids were examined in 4-wk-old, female Wistar rats fed diets of five different Mg-contents of 1/10, 1 (standard diet (Mg 47 mg/100 g diet): control group), 2, 5 and 10-fold of the standard content for 4 wk. In rats fed the 1/10-fold Mg diet, the body weight gain declined with a statistical significance compared to control rats, while no significant differences were observed in rats fed on the 2-, 5-, and 10-fold Mg diets. The imbalance of mineral concentrations in the rats fed 1/10 Mg diet was induced, but in the rats fed high Mg diets were not induced except in tibia. Mg concentration in tibia of rats fed the 10-fold Mg diet significantly increased compared to the control group. All groups (1/10-fold, 2-, 5-, and 10-fold Mg groups) showed no significant changes in tibial mineral levels, except Mg in the 10-fold group, compared to the control group. With increase in Mg-intake, decline of plasma lipid parameters such as cholesterol, triglycerides and phospholipids are induced. Based on these results, it was suggested that a higher Mg-intake (around 5-fold of the standard Mg-content) might have a prophylactic potential against the onset of hyperlipidemia and cardiovascular disease by reducing lipid indices, and Mg decline in bone.

Insinuation of exacerbated oxidative stress in sucrose-fed rats with a low dietary intake of magnesium: Evidence of oxidative damage to proteins

High sucrose diets and low magnesium intake have been independently implicated in induction of oxidative stress in animal models. The aim of this study was to investigate whether low dietary magnesium intake exacerbates the prooxidant effects of high sucrose feeding. Rats were fed control (C), high sucrose (HS); low magnesium (LM) and high sucrose low magnesium (HSLM) diets for 90 days and oxidative stress evaluated in terms of formation of TBARS, advanced oxidation protein products and protein carbonyls. HS and LM rats showed evidence of lipid peroxidation and protein oxidation in plasma and liver. Enhanced oxidative injury to lipids and proteins after HSLM feeding was indicated by increased carbonyl content (p <0.01) and significantly (p <0.005) higher levels of TBARS in plasma and hepatic tissue relative to both HS and LM groups. Altogether, these results illustrate the potential detrimental and cumulative effects of low magnesium intake combined with high sucrose consumption on oxidative stress variables.

Other relevant components of nuts: phytosterols, folate and minerals

Nuts contain significant amounts of essential micronutrients that are associated with an improved health status when consumed at doses beyond those necessary to prevent deficiency states. Nuts do not contain cholesterol, but they are rich in chemically related phytosterols, a class of compounds that interfere with intestinal cholesterol absorption and thus help lower blood cholesterol. Nuts also contain folate, a B-vitamin necessary for normal cellular function that plays an important role in detoxifying homocysteine, a sulphur-containing amino acid with atherothrombotic properties that accumulates in plasma when folate status is subnormal. Compared to other common foodstuffs, nuts have an optimal nutritional density with respect to healthy minerals, such as calcium, magnesium and potassium. Like that of most vegetables, the sodium content of nuts is very low. A high intake of calcium, magnesium and potassium, together with a low sodium intake, is associated with protection against bone demineralisation, arterial hypertension, insulin resistance, and overall cardiovascular risk. Phytosterols might justify part of the cholesterol-lowering effect of nut intake beyond that attributable to fatty acid exchange, while the mineral richness of nuts probably contributes to the prevention of diabetes and coronary heart disease observed in epidemiological studies in association with frequent nut consumption.

Dietary Magnesium Intake and Risk of Incident Hypertension Among Middle-Aged and Older US Women in a 10-Year Follow-Up Study

To assess the hypothesis that magnesium intake is beneficial in the primary prevention of hypertension, 28,349 female United States health professionals aged > or =45 years participating in the Women's Health Study (WHS), who initially reported normal blood pressure (systolic blood pressure <140 mm Hg, diastolic blood pressure <90 mm Hg, no history of hypertension or antihypertensive medications), were prospectively studied. A semi-quantitative food frequency questionnaire was used to estimate magnesium intake. During a median follow-up of 9.8 years, 8,544 women developed incident hypertension. After adjustment for age and randomized treatment, magnesium intake was inversely associated with the risk for developing hypertension; women in the highest quintile (median 434 mg/day) had a decreased risk for hypertension (relative risk 0.87, 95% confidence interval [CI] 0.81 to 0.93, p for trend <0.0001) compared with those in the lowest quintile (median 256 mg/day). This inverse association was attenuated but remained significant after further adjustment for known risk factors. In the fully adjusted model, the relative risks were 1.00 (95% CI 0.95 to 1.10), 1.02 (95% CI 0.95 to 1.10), 0.96 (95% CI 0.89 to 1.03), and 0.93 (95% CI 0.86 to 1.02) (p for trend = 0.03). Similar associations were observed for women who never smoked and reported no history of high cholesterol or diabetes at baseline. In conclusion, the results suggest that higher intake of dietary magnesium may have a modest effect on the development of hypertension in women.

Total Magnesium Intake and Colorectal Cancer Incidence in Women

Magnesium is an essential ion that has an important role in regulating cell cycles and maintaining genomic stability ([1][1]). Administration of supplemental magnesium in animals with experimentally induced colon cancer resulted in fewer colon tumors and smaller cryptal cells of the colon ([2][2]),

Magnesium Intake and Incidence of Metabolic Syndrome Among Young Adults

Studies suggest that magnesium intake may be inversely related to risk of hypertension and type 2 diabetes mellitus and that higher intake of magnesium may decrease blood triglycerides and increase high-density lipoprotein (HDL) cholesterol levels. However, the longitudinal association of magnesium intake and incidence of metabolic syndrome has not been investigated. We prospectively examined the relations between magnesium intake and incident metabolic syndrome and its components among 4637 Americans, aged 18 to 30 years, who were free from metabolic syndrome and diabetes at baseline. Metabolic syndrome was diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III definition. Diet was assessed by an interviewer-administered quantitative food frequency questionnaire, and magnesium intake was derived from the nutrient database developed by the Minnesota Nutrition Coordinating Center. During the 15 years of follow-up, 608 incident cases of the metabolic syndrome were identified. Magnesium intake was inversely associated with incidence of metabolic syndrome after adjustment for major lifestyle and dietary variables and baseline status of each component of the metabolic syndrome. Compared with those in the lowest quartile of magnesium intake, multivariable-adjusted hazard ratio of metabolic syndrome for participants in the highest quartile was 0.69 (95% confidence interval [CI], 0.52 to 0.91; P for trend <0.01). The inverse associations were not materially modified by gender and race. Magnesium intake was also inversely related to individual component of the metabolic syndrome and fasting insulin levels. Our findings suggest that young adults with higher magnesium intake have lower risk of development of metabolic syndrome.

Dietary Glycemic Index, Glycemic Load, Cereal Fiber, and Plasma Adiponectin Concentration in Diabetic Men

Adiponectin may improve insulin sensitivity, reduce inflammation, and ameliorate glycemic control. However, few studies have evaluated dietary predictors of plasma adiponectin levels, especially among subjects with type 2 diabetes. To examine the associations of dietary glycemic load, glycemic index, and fibers with plasma adiponectin levels, we conducted a cross-sectional analysis in 780 diabetic men from the Health Professionals' Follow-up Study. Dietary information was obtained in 1986, 1990, and 1994 using semiquantitative food-frequency questionnaires. After adjustment for age, BMI, smoking, alcohol consumption, physical activity, aspirin use, HbA(1c), history of hypertension or hypercholesterolemia, and fiber intake, dietary glycemic index and glycemic load were inversely associated with plasma adiponectin in a dose-dependent fashion (P for trend = 0.005 for glycemic index and 0.004 for glycemic load). Adiponectin levels were 13% lower in the highest quintile of dietary glycemic index than in the lowest quintile. For dietary glycemic load, adiponectin levels were 18% lower in the highest quintile than in the lowest. In contrast, high intake of cereal fiber was associated with increased plasma adiponectin levels, adjusting for lifestyle factors and dietary glycemic load (P for trend = 0.003). Adiponectin levels were 19% higher in the highest quintile than in the lowest quintile. Higher magnesium intake was also associated with increased plasma adiponectin. Diets low in glycemic load and high in fiber may increase plasma adiponectin concentrations in diabetic patients.

Magnesium Intake in Relation to Risk of Colorectal Cancer in Women

Animal studies have suggested that dietary magnesium may play a role in the prevention of colorectal cancer, but data in humans are lacking. To evaluate the hypothesis that a high magnesium intake reduces the risk of colorectal cancer in women. The Swedish Mammography Cohort, a population-based prospective cohort of 61,433 women aged 40 to 75 years without previous diagnosis of cancer at baseline from 1987 to 1990. Incident invasive colorectal cancer. During a mean of 14.8 years (911 042 person-years) of follow-up, 805 incident colorectal cancer cases were diagnosed. After adjustment for potential confounders, we observed an inverse association of magnesium intake with the risk of colorectal cancer (P for trend = .006). Compared with women in the lowest quintile of magnesium intake, the multivariate rate ratio (RR) was 0.59 (95% confidence interval [CI], 0.40-0.87) for those in the highest quintile. The inverse association was observed for both colon (RR, 0.66; 95% CI, 0.41-1.07) and rectal cancer (RR, 0.45; 95% CI, 0.22-0.89). This population-based prospective study suggests that a high magnesium intake may reduce the occurrence of colorectal cancer in women.

High intake of magnesium in relation to the ruminal transmural potential difference and magnesium absorption in wethers.

High potassium (K) intakes are known to decrease magnesium (Mg) absorption in ruminants by increasing the transmural potential difference (PDt, serosal side = positive). High Mg intakes are known to increase the amount of Mg absorbed, which may be explained by increasing the ruminal Mg concentration, but an effect on the PDt cannot be excluded. The objective of this study was to determine whether or not Mg intake affects the PDt. In a 3 x 3 Latin square design, six ruminally fistulated wethers were fed a low-Mg, low-K ration (3.88 g Mg/kg dry matter (DM); 30.7 g K/kg DM), a high-Mg, low K-ration (16.79 g Mg/kg DM; 30.7 g K/kg DM), and a low-Mg ration high-K (3.88 g Mg/kg DM or 62.1 g K/kg DM). When compared with the low-Mg, low-K ration, the high-Mg, low-K ration raised the absolute apparent Mg absorption (g/day) by 421% and the low-Mg, high-K ration decreased it by 20%. The intake of extra K produced a significant increase in the PDt. The intake of extra Mg did not change the PDt across the rumen wall but produced a significant increase of the ruminal Mg concentrations. On the basis of the individual values for three rations, the mean post feeding ruminal Mg concentrations were found to be unrelated to the PDt (Pearson's r = -0.329, p = 0.183, n = 18). Thus, it is concluded that the observed increase in Mg absorption after a high Mg intake can be explained by an increase in the ruminal Mg concentration rather than by a change in PDt.

Effect of high magnesium intake on apparent magnesium absorption in lactating cows

We investigated whether the percentage of apparent magnesium (Mg) absorption in dry cows with a low level of dry matter intake is comparable to that in lactating cows with high feed intake, but fed the same diet in terms of composition. Lactating cows were fed rations with an ingredient and nutrient composition which was identical to the rations that were used in a previous study in dry cows. The trial had a 16×16-day cross-over design and was preceded by a 10-day run-in period. The six non-pregnant, lactating, multiparous cows (Friesian–Holstein × Holstein–Friesian cross) were fed rations with low and high Mg content, the levels being 3.7 and 6.3 g Mg/kg dry matter at a constant dietary potassium (K) concentration of 30.7 g K/kg dry matter. Increasing the level of Mg intake from 68.1 to 116.3 g Mg per day resulted in absolute Mg absorptions of 9.0 and 18.5 g Mg per day ( P=0.005). Mg absorption, expressed as a fraction of intake, for the low and high-Mg rations was 0.131 and 0.159 ( P=0.183) these values being similar to those observed earlier in dry cows. Milk production was not significantly influenced by the level of Mg intake ( P=0.075). The combined results of this experiment and that of an earlier one with dry cows indicate that absolute apparent Mg absorption (g per day) depends on dietary Mg intake rather than on dry matter intake and physiological status. Thus, lactating and dry cows are equally efficient in Mg absorption, justifying the use of dry cows as a model for lactating cows.