Hezel MP, Liu M, Schiffer TA, Larsen FJ, Checa A, Wheelock CE, Carlström M, Lundberg JO, Weitzberg E. Effects of long-term dietary nitrate supplementation in mice.
Redox Biol 2015;
5:234-242. [PMID:
26068891 PMCID:
PMC4475696 DOI:
10.1016/j.redox.2015.05.004]
[Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 05/26/2015] [Accepted: 05/26/2015] [Indexed: 01/23/2023] Open
Abstract
Background
Inorganic nitrate (NO3-) is a precursor of nitric oxide (NO) in the body and a large number of short-term studies with dietary nitrate supplementation in animals and humans show beneficial effects on cardiovascular health, exercise efficiency, host defense and ischemia reperfusion injury. In contrast, there is a long withstanding concern regarding the putative adverse effects of chronic nitrate exposure related to cancer and adverse hormonal effects. To address these concerns we performed in mice, a physiological and biochemical multi-analysis on the effects of long-term dietary nitrate supplementation.
Design
7 week-old C57BL/6 mice were put on a low-nitrate chow and at 20 weeks-old were treated with NaNO3 (1 mmol/L) or NaCl (1 mmol/L, control) in the drinking water. The groups were monitored for weight gain, food and water consumption, blood pressure, glucose metabolism, body composition and oxygen consumption until one group was reduced to eight animals due to death or illness. At that point remaining animals were sacrificed and blood and tissues were analyzed with respect to metabolism, cardiovascular function, inflammation, and oxidative stress.
Results
Animals were supplemented for 17 months before final sacrifice. Body composition, oxygen consumption, blood pressure, glucose tolerance were measured during the experiment, and vascular reactivity and muscle mitochondrial efficiency measured at the end of the experiment with no differences identified between groups. Nitrate supplementation was associated with improved insulin response, decreased plasma IL-10 and a trend towards improved survival.
Conclusions
Long term dietary nitrate in mice, at levels similar to the upper intake range in the western society, is not detrimental.
Long term dietary nitrate supplementation for 17 months in mice.
Nitrate treatment in the upper range in the western society diet, has no adverse health effects.
Chronic nitrate intake in mice improves fasting insulin and insulin response.
Cardiovascular and inflammatory parameters were unchanged after long-term dietary nitrate treatment.
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