Submitted to: Journal of American College of Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/1/1999
Publication Date: 2/1/2000
Citation: Milne, D.B., Nielsen, F.H. 2000. The interaction between dietary fructose and magnesium adversely affects macromineral homeostasis in men. 19:31-37. Interpretive Summary: Dietary surveys have indicated that over the past 20 years, high-fructose sweetener consumption has increased by more than 700 percent. During the same period, surveys have indicated a decline to marginal or suboptimal intakes of magnesium and calcium. Studies with animals have shown that dietary fructose at 20 percent of energy makes the signs of magnesium deficiency worse and increases kidney calcium concentrations. Because of this interaction and the potential that many individuals are consuming diets that are high in fructose and low in magnesium, we studied this interaction in men. When young men were fed fructose at 20 percent of energy in the diet for six weeks, it upset their balance of major bone minerals; they retained less calcium and lost more phosphorous than they ate. The effect on the bone minerals was greatest when the diets were also low in magnesium. These findings indicate that dietary fructose adversely affects macromineral metabolism in humans and suggests further studies to see if a high fructose diet coupled with low magnesium and marginal calcium leads to bone loss.
Technical Abstract: Studies with rats have found that an interaction between fructose and magnesium affects macromineral metabolism; high dietary fructose significantly increased kidney calcification in both male and female rats, particularly when dietary magnesium was low. To evaluate whether this interaction occurs in humans, eleven men aged 22-40 y were fed a mixed, Western diet for four 42 d dietary periods in which dietary magnesium was either approximately 170 or 370 mg/d, and dietary fructose was either 4 or 19% of energy. A decaffeinated beverage containing high fructose corn syrup replaced cornstarch, bread and rice in the low fructose diet to give the high fructose diet. High dietary fructose significantly (P<0.01) increased magnesium balance, during both low and high dietary magnesium intakes. Ultrafilterable and ionized serum magnesium also apparently were related to magnesium and fructose intakes; they were higher when fructose was fed and when Mg intakes were high. High fructose depressed calcium balance: the effect tended to be more marked when dietary Mg was low. High dietary fructose also significantly (P<0.005) decreased phosphorous balance. Urinary phosphorous losses were significantly (P<0.001) higher when high dietary fructose was fed. High dietary fructose also increased the concentration of serum alkaline phosphatase (P<0.005). These findings indicate that dietary fructose adversely affects macromineral metabolism in humans and suggests further studies to see if a high fructose diet coupled with low dietary magnesium and marginal calcium leads to bone loss.