Zinc Absorption from Milk Is Affected by Dilution but Not by Thermal Processing, and Milk Enhances Absorption of Zinc from High-Phytate Rice in Young Dutch Women

Abstract

Milk has been suggested to increase zinc absorption. The effect of processing and the ability of milk to enhance zinc absorption from other foods has not been measured directly in humans. We aimed to assess zinc absorption from ) milk undergoing various processing and preparatory steps and) from intrinsically labeled high-phytate rice consumed with milk or water. Two randomized crossover studies were conducted in healthy young women [age:18-25 y; body mass index (in kg/m): 20-25]: ) a milk study ( = 19) comparing the consumption of 800 mL full-fat ultra-high temperature (UHT) milk [heat-treated milk (HTM)], full-fat UHT milk diluted 1:1 with water [heat-treated milk and water (MW)], water, or unprocessed (raw) milk (UM), each extrinsically labeled with Zn, and) a rice study ( = 18) comparing the consumption of 90 g intrinsically Zn-labeled rice with 600 mL of water [rice and water (RW)] or full-fat UHT milk [rice and milk (RM)]. The fractional absorption of zinc (FAZ) was measured with the double-isotope tracer ratio method. In vitro, we assessed zinc extraction from rice blended into water, UM, or HTM with or without phytate. FAZ from HTM was 25.5% (95% CI: 21.6%, 29.4%) and was not different from UM (27.8%; 95% CI: 24.2%, 31.4%). FAZ from water was higher (72.3%; 95% CI: 68.7%, 75.9%), whereas FAZ from MW was lower (19.7%; 95% CI: 17.5%, 21.9%) than HTM and UM (both < 0.01). FAZ from RM (20.7%; 95% CI: 18.8%, 22.7%) was significantly higher than from RW (12.8%; 95% CI: 10.8%, 14.6%; < 0.01). In vitro, HTM and UM showed several orders of magnitude higher extraction of zinc from rice with HTM than from rice with water at various phytate concentrations. Milk enhanced human FAZ from high-phytate rice by 62% compared with water. Diluting milk with water decreases its absorption-enhancing proprieties, whereas UHT processing does not. This trial was registered at the Dutch trial registry as NTR4267 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4267).

Influence of Dairy Products on Bioavailability of Zinc from Other Food Products: A Review of Complementarity at a Meal Level

“…Moreover, Sandstrom et al [50] reported a significantly (p < 0.05) higher zinc absorption from bovine milk compared to a soy formula (28 vs. 14%) that was high in phytic acid (200 mg/L), which is agrees with the understanding that phytates are powerful inhibitors of zinc uptake [15]. Talsma et al [52], using a dual stable isotope technique, found lower zinc absorption from bovine milk compared to water (25.5 vs. 72.3%). This is probably because water does not contain inhibitory factors that reduce zinc absorption [53].…”

“…In these studies, zinc absorption was determined in vivo by isotope techniques. Talsma et al [52] examined the effect of milk on zinc absorption from rice in 18 young and healthy women using a dual stable isotopes technique and found a significant (p < 0.05) increase (by 62%) in zinc absorption from rice when 90 g of high-phytate rice was consumed together with 600 mL of UHT-treated whole milk, compared to when the same amount of rice was consumed with water. Rosado et al [55] studied zinc absorption in 48 healthy Mexican women, using a stable double isotope technique, and observed that the addition of 250 mL of UHT low-fat milk or 150 g of flavored yogurt to the plant-based test meal, consisting of 120 g of corn tortillas and 200 g of cooked black beans, significantly (p < 0.05) increased zinc absorption by approximately 50% for milk and 68% yoghurt.…”

Organic zinc supplementation in early-lactation dairy cows and its effects on zinc content and distribution in milk and cheese

“…Low dietary intake of absorbable Zn is the primary cause of Zn deficiency. In a study by Talsma et al (2017), consuming a combination of milk and phytate-rich rice increased the total amount of absorbable Zn from rice, suggesting that Zn-rich dairy products can potentially increase dietary absorbable Zn concentration. Ianni et al (2019) found that feeding dairy animals with Zn was a promising method to increase Zn content in dairy products.…”

Effect of intermittent fasting during acrylamide exposure on blood copper, zinc and lead levels in rats

“…Mechanism of alterations of those three elements due to acrylamide exposure and intermittent fasting are not clear but in similar studies (22), acrylamide was shown to exert prominent effect on some other elements (cobalt, vanadium, magnesium, selenium). Absorption of elements taken with diet is closely related with diet content and substances such as phytates directly affect absorption (25). There are no detailed data concerning effects of acrylamide on those food ingredients.…”