What happens if you eat rancid nuts?

In this brief guide, we will answer the query, “What happens if you eat rancid nuts?” and will discuss how to tell if nuts have gone rancid.

What happens if you eat rancid nuts?

Eating rancid nuts can cause digestion problems and other health problems, because lipid oxidation generates potentially toxic products that have shown correlation with inflammatory diseases, as well as cancer, atherosclerosis and aging (3). 

Even if you don’t become ill right away from eating rotten or stale nuts like almonds, walnuts, or cashews, it’s typically not a good idea since it might interfere with digestion or have other negative consequences on your health over the long run.

What are the potential health risks of eating rancid nuts?

The potential health risks of eating rancid nuts are gastric issues in short terms and inflammation in the long terms. Even if you consume rotten nuts, you are unlikely to have any negative consequences other than a bad taste in your mouth. Although rancid nuts might cause stomach and intestinal discomfort, nausea, vomiting, or diarrhea may occur in rare circumstances. 

On the other hand, eating rancid nuts may have a long-term impact on health since rancid oils in nut butter may induce inflammation and carcinogens. The ingestion of oxidized fats leads to the formation of lipid oxidation aldehydes, which are potentially toxic and highly reactive with proteins, phospholipids, and nucleic acids and can be transported into the cell and tissues. These might have health implications by promoting gut inflammation and possibly altering the microbiome (3).

How to Identify and Prevent Nut Rancidity?

Rancid nuts are identified by the rancid odor. To prevent the rancidity of nuts, correct storage is needed. Nuts have a high oil content and fatty acid composition that can render them susceptible to oxidative rancidity and rapid deterioration (2). 

Rancid or stale nuts such as almonds, walnuts, or cashews may not make you ill right away, but it’s typically not recommended since it may cause long-term damage to your health. Lipid oxidation also produces secondary products, such as carbonyl compounds, aldehydes, hydrocarbons, ketones and furans, that are indicators of food quality deterioration. These compounds are volatile and can be identified through typical odor (2). 

The best way to keep nuts fresh for as long as possible is to store them in airtight containers in a cool, dry environment. Nutty wafts fill the air as soon as a package of high-quality nuts is unwrapped. The oxidation of lipids is influenced by environmental factors like temperature, moisture, light and oxygen. Shelf life of nuts may be increased by low temperature and low moisture conditions, added to low moisture content of the nuts, which must be dried prior to storage (4).


Rancidity of oils produces undesirable volatile compounds and off-flavors.

The secondary products derived from the oxidation of lipids are ketones and aldehydes, which have the off-flavors associated with rancid oils (4). 

Lipid oxidation can also lead to a darkening of color by the formation of melanoidins and a loss of color due to free radical destruction of conjugated double bonds (3).

Unappropriate storage conditions causes not only rancidity

In addition to rancidity, inappropriate storage conditions such as high temperatures, relative high humidity, light incidence and long-term storage can significantly influence the formation of aflatoxins in nuts. Mycotoxins are toxigenic secondary metabolites of filamentous fungi and have a cumulative effect with a risk of causing damage in the liver and kidney (5).

How to store nuts so they last longer?

To correctly store nuts in order to make them last longer, moisture, light incidence, and high temperatures must be avoided. The storage conditions, such as humidity, light incidence, oxygen concentration and temperature strongly determine the shelf life of nuts (2). 

Storage of kernels with their skin (testa) on also reduces oxidative rancidity as the skin or testa acts as an oxygen barrier, minimizing lipid oxidation. The use of packages with high humidity, light and oxygen barriers are useful, as well as low temperatures for the storage (2). If you’re concerned about nuts going bad, it’s better to buy smaller quantities rather than bulky sacks. 

Ideal storage conditions for tree nuts are generally low temperatures (from 4 to 15°C), low moisture content (around 2.5%), low relative humidity (40–60%), low oxygen concentration (< 2.5%) and dark conditions (2). The optimal place is inside of a refrigerator. Shelled nuts may be stored in the refrigerator for six months and in the freezer for up to a year. Nuts that haven’t been shelled may last up to two years.

What are nuts and how are they helpful?

Among all of nature’s wealth, nuts are among the most cherished. Including them in your regular diet is the best way to stay healthy. Snacks are excellent, but they may also be utilized in desserts and a wide variety of sweet and savory foods. 

To maintain a healthy diet and lifestyle, you need to stock up on crunchy items in your cupboard. As a source of good fats, nuts protect your heart by reducing the levels of bad cholesterol (LDL) in your blood, which lowers your risk of heart disease. The most popular tree nuts globally include almond, Brazil nut, cashew, hazelnut, macadamia, pecan, pine nut, pistachio and walnut (1) and an annual global trade in excess of $US32 billion (2).

Nuts are high in protein and fiber and may help curb hunger. In general, these foods contain healthy monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid profiles; soluble and insoluble fibers; vitamins E and K; folate; thiamine; minerals such as magnesium, copper, potassium, and selenium; and substances such as xanthophyll carotenoids, antioxidants, and phytosterols compounds, with recognized benefits to human health (1). Nuts may also help regulate mood and improve mental sharpness, according to several studies. As a result, becoming friends with nuts is a wise decision.

There is nothing better than the flavor of nuts! No matter whether you like them roasted or raw, these small delicious packets are sure to please your taste buds. 

To make nut butter, they may be processed into spreads for sandwiches and dairy butter substitutes. The unsaturated fats in nuts are what make them nutritious, but they are also what makes them perishable. 

For a longer amount of time, nuts are more stable than our fresh fruits and vegetables, although they are vulnerable to rancidity. When the oil in nuts oxidizes, the result is rancidity.


In this brief guide, we answered the query, “What happens if you eat rancid nuts?” and discussed how to tell if nuts have gone rancid.


  1. De Souza, Rávila Graziany Machado, et al. Nuts and human health outcomes: a systematic review. Nutrients, 2017, 9, 1311.
  2. Gama, Tsvakai, et al. Quality and shelf life of tree nuts: A review. Sci hortic, 2018, 242, 116-126.
  3. Vieira, Samantha A., Guodong Zhang, and Eric A. Decker. Biological implications of lipid oxidation products. J. Am. Oil Chem.’ Soc., 2017, 94, 339-351.
  4. Ajith, Sabna, et al. Effect of storage temperatures and humidity on proximate composition, peroxide value and iodine value of raw cashew nuts. J Food Sci Technol, 2015, 52, 4631.
  5. Maturová, Hana. Determination of The Presence of Myco-Toxins in Nuts in Stages of Post-Harvest Handling and Storage. Mitteilungen Klosterneuburg, Rebe und Wein, Obstbau und Früchteverwertung, 2019, 69, 208-215.

Was this helpful?

Thanks for your feedback!