Nitrate and Nitrite Content of Human, Formula, Bovine, and Soy Milks: Implications for Dietary Nitrite and Nitrate Recommendations

Abstract

Background: Estimation of nitrate and nitrite concentrations of milk sources may provide insight into potential health risks and benefits of these food sources for infants, children, and adults. The World Health Organization and American Academy of Pediatrics recommends exclusive consumption of human milk for the first 6 months of life. Human milk is known to confer significant nutritional and immunological benefits for the infant. Consumption of formula, cow's, and soy milk may be used as alternatives to human milk for infants. Methods: We sought to estimate potential exposure to nitrate and nitrite in human, formula, bovine, and soy milk to inform total dietary exposure estimates and recommendations. Using sensitive quantitative methodologies, nitrite and nitrate were analyzed in different samples of milk. Results: Human milk concentrations of colostrum (expressed days 1-3 postpartum; n ¼ 12), transition milk (expressed days 3-7 postpartum; n ¼ 17), and mature milk (expressed >7 days postpartum; n ¼ 50) were 0.08 mg/100 mL nitrite and 0.19 mg/100 mL nitrate, 0.001 mg/100 mL nitrite and 0.52 mg/100 mL nitrate, and 0.001 mg/100 mL nitrite and 0.3 mg/100 mL nitrate, respectively, revealing that the absolute amounts of these anions change as the composition of milk changes. When expressed as a percentage of the World Health Organization's Acceptable Daily Intake limits, Silk Ò Soy Vanilla (WhiteWave Foods, Broomfield, CO) intake could result in high nitrate intakes (104% of this standard), while intake of Bright Beginnings Soy Pediatric

Inorganic nitrite and nitrate: evidence to support consideration as dietary nutrients

“…Previously published studies in our lab [26] reveal the presence of high concentrations of nitrite and nitrate in human breast milk consistent with previous reports [27]. Early post-partum breast milk from certain mothers contained the highest nitrite concentration of any food or beverage product tested [28] (near 20µM).…”

“…Early post-partum breast milk from certain mothers contained the highest nitrite concentration of any food or beverage product tested [28] (near 20µM). At birth, the gastrointestinal tract of the infant is sterile, and it is rapidly colonized by bacteria originating from the mother and the environment [29].…”

Dietary Nitrates, Nitrites, and Cardiovascular Disease

“…Fourth, provision of dietary nitrate, such as beetroot juice (or single servings of spinach, vegetable juices such as V8 juice [Campbell Soup Company, Camden, NJ]) [43], dietary nitrate [47], or in a traditional Japanese dietary pattern [46••], is effective in lowering blood pressure in humans. Fifth, human infants consuming breast milk are exposed to nitrate and nitrite in human milk from birth [51].…”

Dietary intake and bio-activation of nitrite and nitrate in newborn infants

“…Breast milk nitrite concentrations also fall during the first few weeks of life, with the highest levels found in colostrum and decreasing to nearly undetectable amounts in milk collected after the third week postpartum (9,10). The levels of nitrate and nitrite in artificial milk vary widely across a range that extends above and below concentrations measured in breast milk, averaging 43 and 0.3 μmol/l, respectively (10) (Figure 2).…”

“…In an effort to protect against toxicity, the Environmental Protection Agency has set limits on inorganic nitrate and nitrite levels in drinking water and the World Health Organization has put forward acceptable daily intakes for nitrate at 3.7 mg/kg of body weight and for nitrite at 0.06mg/kg of body weight. These levels are easily exceeded, however, with a high vegetable diet, and some have called for a resetting of these limits based on recent advances in our understanding of the roles of dietary nitrate and nitrite (9). The upper limits of toxicity of dietary nitrate in newborns have been investigated.…”