Acorns are the nuts of oak trees, which grow abundantly across the globe.
Once a staple food for various societies, acorns are not as frequently consumed today (1).
Though these nuts are packed with nutrients, it’s often debated whether they’re safe to eat.
This article tells you whether acorns are edible and explores their nutrients, benefits, and dangers.
Acorns have gained a bad reputation because they contain tannins — a group of bitter plant compounds that may be harmful when consumed in high amounts.
Additionally, consuming high amounts of tannins may lead to adverse health effects, such as severe liver damage and cancer ().
However, most of the tannins leach out of acorns when they’re prepared for consumption — often by soaking or boiling. While no studies exist on the toxicity of raw acorns in humans, these nuts are rarely eaten raw (1, ).
Summary While raw acorns harbor high amounts of potentially harmful plant compounds called tannins, properly cooked acorns are low in tannins and generally safe to eat.
Though the exact nutrient profile depends on the species of acorn, all are packed with essential nutrients.
Acorns are especially high in potassium, iron, vitamins A and E, and several other important minerals ().
Plus, these nuts are low in calories. Most of their calories come in the form of healthy unsaturated fats (9).
A 1-ounce (28-gram) serving of dried acorns contains the following nutrients (1, , ):
- Calories: 144
- Protein: 2 grams
- Fat: 9 grams
- Carbs: 15 grams
- Fiber: 4 grams
- Vitamin A: 44% of the Reference Daily Intake (RDI)
- Vitamin E: 20% of the RDI
- Iron: 19% of the RDI
- Manganese: 19% of the RDI
- Potassium: 12% of the RDI
- Vitamin B6: 10% of the RDI
- Folate: 8% of the RDI
Scientists have also identified over 60 beneficial plant compounds in acorns, including catechins, resveratrol, quercetin, and gallic acid — potent antioxidants that can help protect your cells from damage (1).
These antioxidants are linked to numerous health benefits, such as a lower risk of heart disease, diabetes, and cancer (, 13).
Summary Acorns are packed with healthy fats, vitamins, minerals, and plant compounds. They are particularly good sources of vitamins A and E.
Acorns may have several health benefits, as long as they’re properly prepared and not eaten raw.
May improve gut health
The bacteria in your gut play a key role in your overall health. An imbalance of these bacteria has been linked to obesity, diabetes, and bowel diseases (, , , ).
Acorns are a great source of fiber, which nourishes your beneficial gut bacteria (, ).
Additionally, acorns have long been used as an herbal remedy to treat stomach pain, bloating, nausea, diarrhea, and other common digestive complaints ().
In a 2-month study in 23 adults with persistent indigestion, those who took 100 mg of acorn extract had less overall stomach pain than those who took a cornstarch capsule ().
However, this study used highly concentrated extract. It’s not known whether whole acorns would have the same effect.
More research on their digestive effects is needed.
Rich in antioxidants
Antioxidants are compounds that defend your cells from damage caused by potentially harmful molecules called free radicals ().
Research suggests that diets high in antioxidants may help prevent chronic illnesses, such as heart disease, diabetes, and certain cancers (, , ).
One animal study noted that an antioxidant-rich acorn extract reduced inflammation in rats with reproductive damage ().
That said, human research is needed.
Abundant in the wild
Over 450 species of oak worldwide produce acorns. These are mainly in the Northern Hemisphere (1).
From fall to early spring, you can find hundreds — if not thousands — of mature acorns on the ground below these trees. These nuts are considered safe to forage, but you should watch out for rotten ones. Green, unripe specimens should likewise not be gathered.
If collected in the wild, acorns can be a free, nutritious, and sustainable local food choice.
Summary Acorns, which are loaded with fiber and antioxidants, may have several benefits. These include improved gut health and a lower risk of chronic illnesses.
Although acorns offer several benefits, they also have potential drawbacks.
Raw ones may be unsafe
As mentioned above, the tannins in raw acorns function as antinutrients, reducing your absorption of certain food compounds. They’re also linked to certain cancers and may cause liver damage when consumed in high amounts (2, ).
Some people report nausea and constipation from raw acorns, though this has not been confirmed by research. What’s more, the tannins give these nuts a bitter flavor.
Thus, is not recommended to eat raw acorns (1).
You can easily remove the tannins by boiling or soaking your acorns. This process eliminates their bitterness and makes them safe to eat.
May cause allergic reactions
Acorns are a tree nut, which is one of the most common allergens worldwide.
In fact, up to 1.2% of the U.S. population is allergic to one or more tree nuts ().
Allergic reactions to tree nuts range from mild itching, scratchy throat, and watery eyes to anaphylaxis — a potentially life-threatening response that can cause extreme difficulty breathing ().
If you’re allergic to other tree nuts, you should avoid acorns unless cleared to consume them by your healthcare practitioner.
Can be difficult to prepare
Collecting and preparing acorns can be time-consuming. Though abundant in the wild, they’re not commonly sold in grocery stores.
You may need to order them online if you’re unable to forage your own.
You also have to leach them of their tannins to reduce their bitterness and ensure that they are safe to eat. This can be done by boiling or soaking.
Though this process is quite simple, it may feel cumbersome — especially since other nuts are readily available and much easier to eat.
Summary Acorns may have several downsides, including allergic reactions. In addition, raw acorns harbor poisonous tannins and are not recommended for consumption.
Raw acorns contain high amounts of tannins — a chemical that makes them bitter and possibly unsafe to eat in large quantities.
Nonetheless, it’s possible to remove the tannins in several ways.
One of these methods is boiling. Foragers and harvesters often recommend the following steps:
- Look for fully mature, brown acorns with the caps still attached. Avoid green, unripe acorns, as these are higher in tannins.
- Rinse your acorns thoroughly to remove any contaminants, such as dirt and small insects. Throw out any rotten nuts.
- Remove the hard shells using a nutcracker.
- Boil the raw acorns in a pot for 5 minutes, or until the water turns dark brown. Strain the nuts using a colander, discarding the dark water.
- Repeat this step until the water boils clear.
After the tannins are leached out, the nuts are considered safe to eat. You can roast them in the oven at 375°F (190°C) for 15–20 minutes for a quick and nutritious snack.
Summary Foraged acorns should be cleaned, shelled, and boiled to reduce their levels of harmful tannins. They can then be roasted for an easy snack or ground into flour for baking.
Raw acorns are considered unsafe due to their tannins, which are toxic if consumed in high amounts.
However, you can remove the tannins by boiling or soaking. Properly prepared acorns are perfectly edible and full of nutrients like iron and manganese. Delicious roasted, they can also be ground into flour.
If you’re interested in foraging and preparing your own food in the wild, acorns could make an enticing addition to your diet.