Sodium Nitrate vs Monosodium Glutamate: which is worse?

What is Sodium Nitrate?

Sodium nitrate (NaNO3) is a naturally occurring salt found in soil and some plants, and also synthetically produced for use as a food preservative and curing agent. It is converted to sodium nitrite by bacterial action in foods or in the body, where it exerts its preservative and curing effects. Sometimes called 'Chile saltpeter' after its natural South American ore source.

What is Monosodium Glutamate?

Monosodium glutamate (MSG) is the sodium salt of glutamic acid, a naturally occurring non-essential amino acid found in many proteins. It is used as a flavor enhancer to intensify umami (savory) taste. MSG was first isolated from seaweed in 1908 by Japanese chemist Kikunae Ikeda and has been used commercially since then.

Documented risks

Sodium Nitrate: Sodium nitrate shares the same health concerns as sodium nitrite: conversion to nitrosamines is the primary mechanism of concern. Sodium nitrate is converted to nitrite by bacterial reduction in foods and by nitrate-reducing bacteria in saliva before reaching the stomach. The subsequent conversion of nitrite to nitrosamines carries the same carcinogenicity concerns described for sodium nitrite. IARC's 2015 classification of processed meat as Group 1 human carcinogen applies to all nitrite/nitrate-cured processed meats. EFSA's 2017 re-evaluation established acceptable daily intakes (ADIs) for nitrate (3.7 mg/kg body weight/day) and nitrite (0.07 mg/kg body weight/day) based on risk assessment. A notable paradox in nitrate nutrition: dietary nitrate from vegetables (particularly leafy greens like spinach, arugula, and lettuce, and root vegetables like beets) is associated with cardioprotective effects through the nitrate-nitrite-NO pathway, where nitric oxide from dietary nitrate improves vascular function and reduces blood pressure. This beneficial effect of vegetable nitrate contrasts with the potential harm from processed meat nitrate/nitrite, suggesting that the food matrix and associated compounds (antioxidants in vegetables vs. amines in meat protein) significantly influence whether nitrite produces beneficial or harmful effects. Infant exposure to high nitrate levels — particularly from well water — can cause methemoglobinemia ('blue baby syndrome'). The EU and WHO set strict nitrate limits for infant water and food for this reason.

Monosodium Glutamate: MSG safety has been one of the most extensively debated food additive questions in the past 50 years. The 'Chinese Restaurant Syndrome' — a cluster of symptoms (headache, flushing, sweating, chest tightness) reported after eating Chinese food — was attributed to MSG in a 1968 letter in the New England Journal of Medicine. This set off decades of controversy. Multiple rigorous double-blind, placebo-controlled trials have failed to consistently demonstrate that MSG at doses present in food causes these symptoms when participants do not know whether they received MSG or a placebo. A comprehensive 1993 review by the FDA-commissioned Federation of American Societies for Experimental Biology (FASEB) found that while some sensitive individuals may experience symptoms at high doses (>3g of pure MSG on an empty stomach), the doses in typical food servings do not consistently produce symptoms in double-blind conditions. The FDA classifies MSG as GRAS (generally recognized as safe). EFSA's 2017 re-evaluation set an ADI of 30 mg/kg body weight per day, acknowledging that very high doses could affect neurological function but concluding typical dietary exposure is safe. Critics including Dr. Russell Blaylock and advocacy groups have argued that MSG is an 'excitotoxin' — a compound that overstimulates glutamate receptors in the brain and could cause neuronal damage. While glutamate is indeed a neurotransmitter and high-dose glutamate can cause neurotoxicity in animal models, the blood-brain barrier and normal metabolic regulation are generally considered sufficient to prevent dietary MSG from affecting brain glutamate levels. A 2018 EFSA re-evaluation noted that combined exposure to glutamates from all sources (including naturally occurring glutamate in protein-rich foods and other added glutamates E621-E625) could approach the new lower ADI in high consumers — a concern particularly for children with high processed food intake.