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BackgroundPrevious research has shown that ingestion of substances that enhance the body's hydrogen ion buffering capacity during high intensity exercise can improve exercise performance. The present study aimed to determine whether the chronic ingestion of an alkalizing supplement, which purports to enhance both intracellular and extracellular buffering capacity, could impact cardiorespiratory and performance markers in trained Nordic skiers.MethodsTwenty-four skiers (12 men, 12 women), matched for upper body power (UBP), were split into treatment and placebo groups. The treatment group ingested Alka-Myte®-based alkalizing tablets (1 tablet/22.7 kg body mass/day) over seven successive days while the placebo group consumed placebo tablets (i.e., no Alka-Myte®) at the same dosage. Prior to tablet ingestion (i.e., pre-testing), both groups completed a constant power UBP test, three successive 10-sec UBP tests, and then a 60-sec UBP test. Next, skiers completed the 7-day ingestion of their assigned tablets followed immediately by a repeat of the same UBP tests (i.e., post-testing). Neither the skiers nor the researchers were aware of which tablets were being consumed by either group until after all testing was complete. Dependent measures for analysis included heart rate (HR), oxygen consumption (VO2), minute ventilation (VE), blood lactate (LA), as well as 10-sec (W10, W) and 60-sec (W60, W) UBP. All data were evaluated using a two-factor multivariate repeated measures ANOVA with planned contrasts for post-hoc testing (alpha = 0.05).ResultsPost-testing cardiorespiratory (HR, VO2, VE) and LA measures for the treatment group tended to be significantly lower when measured for both constant power and UBP60 tests, while measures of both 10-sec (W10: 229 to 243 W) and 60-sec UBP (W60: 190 to 198 W) were significantly higher (P < 0.05). In contrast, there were no significant changes for the placebo group (P > 0.05).ConclusionsFollowing the 7-day loading phase of Alka-Myte®-based alkalizing tablets, trained Nordic skiers experienced significantly lower cardiorespiratory stress, lower blood lactate responses, and higher UBP measures. Thus, the use of this supplement appeared to impart an ergogenic benefit to the skiers that may be similar to the effects expected from consuming well-studied extracellular buffering agents such as sodium bicarbonate.

Effects of dietary calcium on mammary carcinogenesis in rats were investigated because of evidence that calcium counteracts the promotion of colon cancer by dietary fat and because experimental diets for rats normally contain higher amounts of calcium and vitamin D than do human diets. Our earlier experiments indicated that yields of tumors induced in young, Sprague-Dawley rats by 7,12-dimethylbenz(a)-anthracene (DMBA) were higher when dietary calcium, phosphate, and vitamin D were decreased. Results of an experiment in which dietary amounts of calcium, phosphate, and vitamin D were varied independently suggested that phosphate and vitamin D have interactive effects with calcium. Another experiment in which dietary vitamin D alone was varied provided evidence that higher amounts inhibited tumorigenesis in the presence of low amounts of calcium and phosphate but the results with a high-calcium and -phosphate diet were inconclusive. The findings suggest that low amounts of dietary calcium and vitamin D and high amounts of phosphate increase susceptibility to DMBA-induced mammary neoplasia.

Dietary fiber is one of several variables being considered in the study of the relationship between diet and cancer. Intervention trials in which dietary fiber is increased are the most direct way of assessing the possible role of fiber in this disease. Two dietary snack products have been developed for use in a fiber intervention study: the high-fiber snack (HFS), which supplies 23 g of dietary fiber per day (mostly from wheat bran) and the low-fiber product (LFS), which provides 3.5 g. Over a 12-week period, 28 volunteers consumed the HFS for 6 weeks and the LFS for 6 weeks. Compliance, as assessed by reports, through recovery of a riboflavin marker in the urine and fecal fiber analysis, was good. The only adverse effects reported were mild abdominal discomfort and gas. Serum ferritin and calcium decreased in some subjects, indicating a need to supplement the products with these essential minerals. Consumption of the snacks did not affect total energy intake or the intake of the nutrients monitored.