An elevated anion gap and metabolic acidosis can be due to several factors, including electrolyte, vitamin, and mineral imbalances. You must evaluate the client’s nutritional status, intake, and risk factors for metabolic acidosis.
The anion gap evaluates metabolic acidosis and calculates the difference between positively charged cations and negatively charged anions in the blood. The equation used is sodium and potassium minus chloride and bicarbonate. The anion gap actually reflects the anions not represented in the equation. These include proteins, lactate, keto acids, phosphates, sulfates, and other organic anions (Pagana 2021). Normally, as acid builds up, an increase in bicarbonate can neutralize the acid and maintain a normal blood pH of 7.35-7.45 (Sharma 2022).
Therefore, it is important to evaluate the client’s risk factors for metabolic acidosis, including an acid-forming diet lacking in alkalizing factors. The most acid-forming foods are meat, eggs, cheese, and cereal products, while the most alkalizing foods include fruits, vegetables, and potatoes (Limmer 2018).
A buildup of lactic acid can increase the anion gap and may be caused by thiamin insufficiency. Thiamine is essential to energy generation, amino acid metabolism, synthesis of nucleic acids, antioxidant systems, cell membrane stability, myelin sheath maintenance, nerve conduction, and synthesis of glutamate and gamma-aminobutyric acid (GABA) (Hammond 2013). Research suggests that thiamine deficiency may be associated with vascular inflammation, myocardial infarction, heart failure, diabetes, obesity, conduction deficits, and depression (Eshak 2018).
It is important to evaluate the client’s risk of thiamin insufficiency, including intake of excess carbohydrates and insufficient thiamin intake. Since thiamin plays such an important role in glucose metabolism, an increase in dietary carbohydrates increases the relative need for thiamin (Dhir 2019).
An elevated anion gap very well may be common, considering the widespread consumption of a highly processed Western-style diet. It is possible that many of the individuals with a high anion gap consume an acid-forming high carbohydrate diet without simultaneously consuming adequate thiamin or minerals, which are also alkalizing.
Note that some labs may calculate the anion gap without potassium which shifts the expected range downward.
You can read more about Anion Gap on the ODX Research Blog here https://www.optimaldx.com/research-blog/metabolic-biomarkers-anion-gap
References
Brinkman, Joshua E. and Sandeep Sharma. “Physiology, Metabolic Alkalosis.” StatPearls, StatPearls Publishing, 18 July 2022.
Dhir, Shibani et al. “Neurological, Psychiatric, and Biochemical Aspects of Thiamine Deficiency in Children and Adults.” Frontiers in psychiatry vol. 10 207. 4 Apr. 2019, doi:10.3389/fpsyt.2019.00207
Limmer, Mirjam et al. “Enhanced 400-m sprint performance in moderately trained participants by a 4-day alkalizing diet: a counterbalanced, randomized controlled trial.” Journal of the International Society of Sports Nutrition vol. 15,1 25. 31 May. 2018, doi:10.1186/s12970-018-0231-1
Pagana, Kathleen Deska, et al. Mosby's Diagnostic and Laboratory Test Reference. 15th ed., Mosby, 2021.