Do cashews contain high levels of oxalic acid and histamine?

Cashews and Their Content of Oxalic Acid and Histamine

Cashews are considered moderate in oxalic acid content and are not classified as high-histamine foods, making them generally acceptable for most individuals except those with specific cashew allergies or severe oxalate restrictions.

Oxalic Acid Content in Cashews

Cashews contain moderate levels of oxalic acid, which is an important consideration for certain populations:

• According to The Lancet Planetary Health guidelines, cashews are not among the highest sources of oxalic acid 1
• Kidney International guidelines specifically list cashews among nuts that calcium stone formers with hyperoxaluria should limit, along with almonds, peanuts, walnuts, and pecans 1
• However, cashews are not in the same category as the highest oxalate foods like spinach and rhubarb, which have extremely low calcium absorption rates (~5%) due to their high oxalic acid content 1

Oxalate Content Comparison

• High oxalate foods (should be strictly limited): spinach, rhubarb, beets
• Moderate oxalate foods (including cashews): should be consumed in moderation by those with calcium oxalate kidney stones or hyperoxaluria
• Low oxalate alternatives: turnip greens, kale, and bok choy (which have calcium absorption rates >50%, even higher than dairy products) 1

Histamine Content in Cashews

Regarding histamine content:

• Cashews are not specifically listed among high-histamine foods in current guidelines 2
• Unlike fermented foods, aged cheeses, or certain preserved meats that are typically high in histamine, cashews do not naturally contain significant amounts of histamine
• Individuals with histamine intolerance may experience symptoms from various foods, but cashews are not typically considered primary triggers 2

Special Considerations

For Kidney Stone Formers

• If you have calcium oxalate kidney stones or hyperoxaluria, moderate your intake of cashews 1
• Consider consuming calcium-rich foods alongside cashews to help bind oxalate in the digestive tract, reducing absorption
• Cooking techniques like soaking can reduce oxalate content in foods through leaching 3

For Allergy Concerns

• Cashews are a known allergen for some individuals, with potential for severe reactions 1
• Cashew allergies can be transferred through organ transplantation, highlighting their potent allergenic properties 1
• Industrial processing of cashews has only minor effects on allergen recognition by IgE antibodies 4

Nutritional Benefits

• Despite these considerations, cashews offer nutritional benefits including cardiovascular protection
• A randomized controlled trial showed that cashew consumption can reduce total and LDL cholesterol when substituted for high-carbohydrate snacks 5

Processing Considerations

Food processing can affect both oxalate and potential AGE (Advanced Glycation End-products) formation in nuts:

• High-temperature cooking methods like roasting can increase AGE formation in nuts, including cashews 1
• Water-based cooking methods (boiling, steaming) and shorter cooking times at lower temperatures produce fewer AGEs 1
• Roasting cashews (typically between 140-180°C) may cause changes to nut lipids and phytochemicals and generate AGEs through the Maillard reaction 1

In one unusual case report, excessive consumption of cashew pseudofruit ("cashew apple," not the nut itself) led to oxalate nephropathy due to its high vitamin C content, which can metabolize to oxalate 6. This highlights that moderation is important even with nutritious foods.