Monosodium Glutamate vs Recombinant Bovine Growth Hormone: which is worse?

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.

What is Recombinant Bovine Growth Hormone?

Recombinant bovine growth hormone (rBGH), also called recombinant bovine somatotropin (rBST), is a synthetically produced version of the naturally occurring cattle growth hormone, manufactured using genetically engineered E. coli bacteria. Injected into dairy cows, it increases milk production by 10-15%. It was FDA-approved in 1993 under the brand name Posilac (originally Monsanto, later Elanco).

Documented risks

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.

Recombinant Bovine Growth Hormone: The central human health concern is that rBGH treatment significantly elevates insulin-like growth factor 1 (IGF-1) levels in treated cows' milk. IGF-1 is a naturally occurring growth hormone that promotes cell growth and division. Multiple epidemiological studies have associated elevated blood IGF-1 levels with increased cancer risk in humans. A 1998 study in The Lancet (Hankinson et al.) found that women with the highest IGF-1 blood levels had approximately 7 times the breast cancer risk compared to those with the lowest levels. A 2004 meta-analysis in JNCI (the Journal of the National Cancer Institute) confirmed significant associations between high IGF-1 levels and breast, prostate, and colorectal cancer risk. The mechanistic question is whether consuming rBGH-treated milk raises blood IGF-1 levels in humans. The FDA and WHO/FAO Codex Alimentarius concluded that IGF-1 in milk is a protein largely digested in the GI tract before absorption. Canadian regulatory researchers challenged this, arguing that pasteurization reduces proteases that would otherwise break down IGF-1, potentially allowing more intact IGF-1 to survive digestion. The Codex Alimentarius Commission made history in 1999 by declining to endorse rBST safety maximum residue limits — a split vote (33 in favor of the MRL, 29 against, with abstentions) demonstrating fundamental international disagreement. This is one of very few cases where Codex failed to establish a safety standard. Animal welfare is a second major concern: Health Canada's comprehensive 1999 review found that rBGH-treated cows had 25% higher rates of clinical mastitis, 50% higher lameness risk, increased reproductive problems, and shortened productive lifespans, requiring substantially more antibiotic treatment — an antibiotic resistance concern. Canada rejected rBGH approval in 1999 after its scientific review; the EU banned it in 1999.