Chestnuts

In this Article (Index)

• Chestnuts
• Health Benefits
• Risks: Allergies
• Nutrients and Bioactive Compounds.
• Phytochemicals
• Vitamins
• Minerals
• Oils and healthy fats
• Fiber
• Chestnut Flour
• Closing Comments

Chestnuts

The chestnut tree belongs to the Fagaceae family and is related to oaks and beeches. Its genus Castanea is widely distributed across the Northern Hemisphere with different species, in Japan (Castanea crenata), China (C. mollissima), Europe (C. sativa), and North America (C. dentanta).

It has been planted for over 5,700 years as shown by remains found in northeastern Greece and southern Bulgaria. During the Middle Ages, chestnut flour was the main ingredient in bread, and it was a handy food resource during periods of famine.
They are consumed roasted, boiled, and even raw.

Global chestnut production was over 2,1 million tons in 2022, with China producing more than 70% of them, followed by Spain and Bolivia.

They have significant quantities of dietary fiber, small amounts of protein (2-4%), and low levels of fatty acids compared to other nuts like almonds, walnuts, or hazelnuts. They are a healthy food. They contain starches, and some natural sugars like sucrose, glucose, fructose, and raffinose.

Health Benefits

Chestnuts are used in gluten-free baked foods as flour. Animal studies have shown that chestnut supplementation (at 1.1% levels) "reduced abdominal adipose tissue... Lower serum cholesterol was also observed in animals supplemented with chestnut... These results suggest that chestnut supplementation may contribute to regulate adipose tissue deposition." (6)

The starches in chestnuts are absorbed at a slower rate than regular wheat flour starch, and this improves blood sugar balance. (4)

Risks: Allergies

Tree nuts are one of the Big Eight food groups responsible for over 90% of food allergy cases in the US. The other seven allergy-causing foods are peanut, milk, shellfish, soy, wheat, egg, and fish.

Tree nut allergies are usually more severe and life-threatening than the allergic reactions caused by eggs, or milk, which are normally mild and short-lived.

Chestnuts are not among the top nuts that cause allergies (like walnuts, peanuts, or almonds), but they can cause severe allergic reactions. (1)

Approximately 1 out of 3 chestnut-allergic persons experience severe anaphylactic reactions if they eat chestnuts. Allergy to chestnuts is also linked to reactivity against pollen, latex, and other foods (bananas, avocados, kiwi, hazelnuts, walnuts, and peanuts). (5)

Take care, allergic reactions can be very serious

Check the food label for the listed allergens ("may contain...", and "Contains..."), it should mention tree nuts (for example: almonds, cashews, pistachios, pecans, walnut, hazelnut) and peanuts (also called ground nut by some). The American FDA also requires the specific identification of tree nuts such as coconut, shea nut, and pine nuts. Also check the "processed" text which could read: "processed at a facility that handles nuts".
When in doubt, avoid the product, and always read the label for ingredients and the text in the "Precautionary allergen labeling" (PAL). Eating out: Ask the waiter questions.

Nutrients and Bioactive Compounds

• Phytochemicals
• Vitamins
• Minerals
• Oils and healthy fats
• Fiber

Phytochemicals

Phenolic Compounds

As with all nuts, chestnuts contain antioxidant compounds (polyphenols). The most abundant compounds in these nuts are gallic acid, vanillic acid, syringic acid, catechin, and ellagic acid. (2)

Vitamins

Chestnuts, together with pistachios have higher concentrations of folic acid than other nuts. Chestnuts have the highest amount of vitamin C.
Below are the Vitamin contents in mg per 100 grams. (2)

Minerals

The following shows the mineral content in chestnuts expressed in mg per 100 grams. (2)

Oils and healthy fats

Chestnuts contain low levels of oils, roughly 1.6 to 7.4% compared to other nuts like almonds, pecan, hazelnuts, or macadamia. However, the fat-soluble plant bioactive compounds are found in these fats in higher quantities than in other nuts (tocols, and phytosterols).
It has high quantities of oleic acid, a monounsaturated fatty acid (MUFA), and linoleic, a polyunsaturated fatty acid or PUFA with a small amount of Linolenic acid, an omega-3 PUFA. (2).
The following table shows its fatty acid composition in g/100 g nut). (2)

Fiber

Chestnuts are a good source of dietary (2.3 to 3.7%). (2)

Chestnut Flour

Chestnut flour is made by drying and grinding these nuts into flour.

Whole chestnut flour has lower levels of digestible starch than wheat flour and a higher level of slowly digestible starch. It has between 70% and 85% of resistant starch plus 4% to 10% of dietary fiber. Chestnut starch is rich in antioxidant polyphenols like phytic acid that are anti-inflammatory and protect against cardiovascular disease.

Replacing white flour with chestnut flour in cakes lowers the speed of starch absorption in the gut and the sugar spike in the blood. (4)

Chestnut flour is used for non-rising flatbreads and pancakes.

Chestnuts are true nuts and are gluten-free. For baking leavened foods you will need a binder like xanthan gum and a rising agent like baking powder. Use it in banana bread, muffins, and cookies.

It has a slightly sweet flavor and a lower glycemic index (GI) than wheat flour.

If gluten isn't a problem you can substitute up to 50% of the wheat flour with chestnut flour without affecting the final product.

Closing Comments

Chestnuts are a healthy nut to add to your diet. They are also a good substitute for all-purpose wheat flour in your baked breads, cakes, or cookies. It promotes cardiovascular health, provides satiety, and essential nutrients, and improves blood sugar levels as well as better cholesterol parameters.