Sodium Aluminum Phosphate vs Red Dye 40: which is worse?

What is Sodium Aluminum Phosphate?

Sodium aluminum phosphate (SALP) is a leavening acid and food additive used in baked goods, particularly self-rising flour and baking powder. It provides a slow, sustained leavening action during baking. SALP is also used as an emulsifying salt in processed cheese products.

What is Red Dye 40?

Red Dye 40 (Allura Red AC) is a synthetic petroleum-derived azo dye that produces a bright red-orange color. It belongs to the monoazo chemical class and is highly water-soluble, with the formula C18H14N2Na2O8S2. It replaced amaranth (Red Dye 2), which was banned in the US in 1976 following cancer concerns.

Documented risks

Sodium Aluminum Phosphate: The primary health concern with SALP is aluminum exposure. Dietary aluminum intake has been studied in relation to neurotoxicity, and there is ongoing scientific debate about whether chronic dietary aluminum exposure contributes to Alzheimer's disease risk. EFSA's 2008 review of dietary aluminum exposure concluded that the tolerable weekly intake (TWI) was being exceeded by some European populations based on total dietary aluminum sources, raising concern. A 2011 EFSA risk assessment noted that certain high-aluminum sources (including baked goods from SALP-containing leavening agents) contributed meaningfully to total dietary aluminum. The WHO has set a PTWI (provisional tolerable weekly intake) of 2 mg/kg body weight/week for total aluminum. However, the causal link between dietary aluminum from food-grade SALP and Alzheimer's disease has not been definitively established in human studies.

Red Dye 40: Red Dye 40 has been linked to several health concerns, particularly in children. The most documented association is with hyperactivity and ADHD-related behavior. A landmark 2007 study in The Lancet (McCann et al.) found that a mixture of six artificial dyes including Red 40, combined with sodium benzoate, significantly increased hyperactivity scores in children ages 3 and 8–9. This prompted EFSA to require the 'may have adverse effect on activity and attention in children' warning label across the EU and UK. A 2012 meta-analysis in Neurotherapeutics (Arnold et al.) confirmed a small but statistically significant deleterious effect of artificial food colors on children's behavior, even in those without diagnosed ADHD. The authors described the effect as a public health issue rather than merely an ADHD issue. Regarding carcinogenicity: commercial batches of Red 40 contain trace amounts of benzidine, an IARC Group 1 human carcinogen. A 1994 study in Food and Chemical Toxicology documented benzidine contamination. The FDA maintains that exposure is below harmful thresholds, but the Center for Science in the Public Interest (CSPI) has cited this contamination in multiple ban petitions. Allergic reactions are documented: Red 40 can trigger histamine release leading to hives, rhinitis, and in rare cases anaphylaxis. Cross-reactivity with aspirin is established in aspirin-sensitive individuals. Gut health: A 2021 study in Nature Communications (Kwon et al.) found Red 40 may worsen inflammatory bowel disease and induce colitis-like symptoms in genetically susceptible mice by triggering immune responses in gut-associated lymphoid tissue. In April 2025, HHS Secretary RFK Jr. announced the FDA would phase out Red 40 and 7 other petroleum-based dyes from the US food supply.