Abstract
Inorganic nitrate and nitrite are plant nutrients, legally mandated additives to processed meats, and components of foods and dietary supplements associated with blood pressure-lowering and performance-enhancing effects. Controversy around dietary nitrate and nitrite consumption exists because of the potential for increased risk of certain cancers in adults and methemoglobinemia (ie, blue baby syndrome) in infants. However, more recent evidence suggests that dietary nitrate, as an exogenous source for endogenous nitric oxide production via the human nitrate-nitrite-nitric oxide pathway, exerts blood pressure-lowering effects and athletic performance-enhancing activities in humans. Nitrate and nitrite content in foods is lacking from nutrient databases, which limits the ability to study health-related epidemiological associations. Therefore, we estimated human nitrate and nitrite intakes from cultural meal patterns, foods, and dietary supplements in order to determine the potential exposure range from available foods.
Generated Summary
This journal article examines the concentrations of dietary nitrate and nitrite in various food patterns and dietary supplements. The study aims to estimate human nitrate and nitrite intake from cultural meal patterns, specific foods, and dietary supplements to determine potential exposure ranges. The research highlights the potential health benefits and risks associated with dietary nitrate and nitrite consumption, focusing on their effects on blood pressure and athletic performance. The methodology includes estimating nitrate and nitrite intakes from various food sources and supplements, recognizing the limitations in current nutrient databases regarding nitrate and nitrite content. The study emphasizes the importance of understanding these concentrations to provide informed dietary guidance and assess the potential for both health benefits and risks, particularly in the context of cardiovascular health and athletic performance. The analysis involves assessing the nitrate and nitrite content of foods and supplements and comparing these values to recommended daily intakes. The scope includes an assessment of meal patterns from different cultures and the potential risks and benefits of nitrate and nitrite intake.
Key Findings & Statistics
- The study notes that the World Health Organization (WHO) has set an acceptable daily intake (ADI) for nitrate at 0-3.7 mg/kg body weight per day, which is equivalent to 222 mg/d for a 60-kg adult, and for nitrite at 0.07 mg/kg body weight per day, or 4.2 mg nitrite per day for a 60-kg adult.
- The article points out that the upper limit represented by the WHO ADI corresponds to the concentration of dietary nitrate that lowers blood pressure in normotensive and hypertensive adults.
- The study mentions that single servings of high-nitrate foods, such as spinach, arugula, and romaine lettuce, may exceed WHO ADI, which raises concerns about the potential health risks and benefits of dietary nitrate and nitrite consumption.
- The research indicates that in Hong Kong, dietary exposure to nitrate from raw vegetables was estimated to be approximately 120% and 350% the ADI for average- and high-vegetable consumers, respectively.
- The study states that nitrate intakes represented by the combination diet or DASH diet increased daily nitrate by 47.1 mg/d compared with the standard American diet, a 20% increase in the ADI resulting from increased vegetable consumption.
- Hord et al. modeled a diet high in nitrate-rich foods in a hypothetical DASH diet and estimated a potential nitrate concentration of approximately 1.2 g nitrate per day.
- The analysis of American meal patterns showed an estimated nitrate intake of 109.8 mg/d and nitrite intake of 0.092 mg/d.
- In the Japanese meal pattern, the estimated nitrate intake was 218.6 mg/d and nitrite intake was 0.121 mg/d.
- The Chinese meal pattern showed an estimated nitrate intake of 231.1 mg/d and nitrite intake of 0.133 mg/d.
- The Indian meal pattern’s estimated nitrate intake was 100.8 mg/d and nitrite intake was 0.112 mg/d.
- The Neo40 supplement contains 22% and 450% of the ADI for nitrate and nitrite, respectively.
- Beet Boost contains approximately 20% of the ADI for nitrate.
- Beet Elite contains approximately 97% and 225% of the ADI for nitrate and nitrite, respectively.
- The article suggests that an adult supplementing their diet with a beetroot juice beverage and 1/2 serving of cooked beets or spinach (310 mg) exceeds the current ADI for a 60 kg-adult.
- An endurance athlete on the DASH diet plan who is taking a supplement will have an approximately 5-fold increase in total exposure to nitrate compared with a 60-kg healthy adult on a standard American diet.
Other Important Findings
- Dietary nitrate and nitrite are plant nutrients and additives in processed meats and dietary supplements, associated with blood pressure-lowering and performance-enhancing effects.
- Controversy exists due to the potential increased cancer risk and methemoglobinemia (blue baby syndrome), but recent evidence suggests dietary nitrate supports nitric oxide production, lowering blood pressure and improving athletic performance.
- Nitrate and nitrite content in food databases is lacking, limiting the ability to study health-related associations.
- Japanese and Chinese diets, rich in leafy greens and root vegetables, showed the highest nitrate and nitrite concentrations.
- American and Indian diets had lower concentrations.
- Consumption of nitrate-rich foods or supplements can exceed the World Health Organization (WHO) acceptable daily intake (ADI) for nitrate.
- Dietary nitrate is converted to nitrite, then to nitric oxide (NO), which benefits endothelial function and metabolic regulation.
- Endothelial dysfunction is linked to cardiovascular risk factors, and dietary nitrate can restore NO homeostasis.
- High nitrate concentrations in drinking water may cause harmful effects, but evidence is not conclusive.
- Nitrate and nitrite are used in cured meats to prevent bacterial growth and affect flavor.
- Vitamin C and flavonoids inhibit nitrosamine formation, while heme iron enhances it.
- Food processing, cooking, and storage can alter nitrate and nitrite concentrations.
- Health effects of nitrate and nitrite exposure vary based on lifestyle, physiological, and environmental factors.
- Intrinsic factors like food composition and extrinsic factors like processing methods impact bioavailability.
- The DASH diet and other healthy dietary patterns may be linked to nitrate and nitrite concentrations in vegetables.
- The World Health Organization’s acceptable daily intake recommendations for nitrate can be exceeded by normal daily intakes of single foods and recommended dietary patterns.
- The study analyzed nitrate and nitrite content in food and supplements using a hot water processing method.
- Leafy greens and fermented foods are richer in nitrate than standard American foods.
- Supplement brands incorporate concentrated forms of vegetables.
- The study notes that an elderly person with heart disease or hypertension will have a much greater need for dietary nitrate and nitrite.
- The article states that the Food Standards Australia New Zealand and the European Food Safety Authority consider the major sources of nitrate and nitrite exposure to be vegetables and fruits.
Limitations Noted in the Document
- The USDA nutrient database currently lacks dietary nitrate and nitrite concentrations of foods, which limits the accuracy of human exposure assessments in epidemiological studies.
- The study acknowledges the inherent variability in dietary nitrate and nitrite exposure, making it difficult to derive simplistic dietary recommendations.
- The study notes that the estimates of dietary nitrate and nitrite exposure are based on meal patterns from specific cultures, and may not be representative of all populations.
- The study also acknowledges that the quantification of nitrate and nitrite in food and supplements may vary depending on the testing methods and the specific products analyzed.
Conclusion
The study emphasizes the significance of understanding the impact of dietary nitrate and nitrite, underscoring their roles in both potential health benefits and risks. “Given the established vasoprotective, performance-enhancing, blood pressure-lowering effects of dietary nitrates in humans, specific recommendations to encourage plant-based, nitrate-rich foods may produce significant public health benefits.” The research highlights that the World Health Organization’s acceptable daily intake for nitrate can be surpassed through regular consumption of certain foods and supplements. It highlights the need for rational dietary guidance regarding nitrate- and nitrite-containing foods to achieve optimal cardiovascular health and athletic performance while considering the potential negative health risks. The study highlights that the DASH diet and other healthy dietary patterns may be linked to nitrate and nitrite concentrations in vegetables. Furthermore, the article points out that the Food Standards Australia New Zealand and the European Food Safety Authority consider the major sources of nitrate and nitrite exposure to be vegetables and fruits. The article supports the notion that specific recommendations should be made to encourage plant-based, nitrate-rich foods as a strategy to enhance public health, focusing on the vasoprotective and performance-enhancing benefits of dietary nitrates.