7 Side Effects of Eating Too Many Almonds

Eating too much of this nutty tidbit can be more harmful than you think.

Medically Reviewed by Reda Elmardi, RDN
By Ravi Teja Tadimalla, Professional Certificate In Food, Nutrition & Health

A few side effects of almonds may make you wonder if you should consume them. Almonds are crunchy, nourishing, and delicious. They have many culinary uses and make a great snack. These nuts provide numerous health benefits and are a great source of nutrients.

However, studies found that excessive consumption of almonds can cause adverse effects. This article examines the side effects of almonds and any potential drug interactions. Read on.

What Are The Side Effects Of Almonds?

1. May Cause Constipation

Almonds are rich in fiber. An ounce of almonds (about 23 kernels) contains 3.5 grams of fiber (1). Though this is good, excess intake of fiber can lead to constipation and a host of other gastrointestinal issues if not combined with enough water intake(2).

Other gastrointestinal symptoms caused by excess intake of almonds (and their fiber) are bloating, gas, stomach cramps, and diarrhea (3).

2. Decrease Nutrient Absorption

The excess fiber can also bind with other minerals (like calcium, magnesium, zinc, and iron) and interfere with their absorption in the bloodstream (3). Consume almonds as a single snack or in between meals to get full benefits of the nuts.

The recommended daily fiber intake is about 30 grams for most people (4). Anything beyond that can cause issues.

3. May Cause Weight Gain

An ounce of almonds (23 kernels) contains about 164 calories (1). Though this is not a problem by itself, if you consume almonds in excess (more than 20), on top of your regular diet, you can pile on pounds.

This is especially true if you do not indulge in regular physical exercise.

It is highly unlikely almonds by themselves can cause weight gain. Consuming them in excess as well as following a poor lifestyle makes one prone to weight gain.

4. Can Lead To Allergies

After walnuts and cashews, almonds cause most tree nut allergies in the US (5).

Amandin, a protein in almonds, has been identified as an allergen (5).

Almonds may cause oral allergy syndrome in certain individuals. The symptoms include itchy mouth, scratchy throat, and swelling of the tongue, mouth, and lips (6).

Almonds also can cause a much severe allergic reaction called anaphylaxis (7). This condition is characterized by shortness of breath, hives, nausea or vomiting, confusion, impaired voice, low blood pressure, and lightheadedness.

5. May Lead To Vitamin E Overdose

Almonds are rich in vitamin E. But consuming them in excess may lead to vitamin E overdose.

Though overdosing on vitamin E by merely eating almonds is highly unlikely (one cannot just eat so many almonds!), it is essential we are aware of the repercussions.

If you are already consuming other foods rich in vitamin E (like fortified cereals and whole grains), excess of almonds can cause problems.

Excess intake of vitamin E can interrupt blood coagulation and lead to hemorrhage (8). However, these effects are more prominent in individuals taking excess of vitamin E supplements.

6. May Cause Kidney Stones

Almonds are rich in intestinal soluble oxalates, which are compounds that may contribute to renal failure and kidney stones. Reports suggest that oxalates from almonds have a high bioavailability (9).

A hundred grams of roasted almonds contains 469 milligrams of oxalate (10).

7. Increase Toxins In The Body

Almonds, especially bitter versions, can cause cyanide poisoning. The HCN level is 40 times higher in bitter almonds as compared to sweet almonds (11).

After enzymatic hydrolysis, hydrocyanic acid (HCN) may lead to breathing issues, nervous breakdown, choking, and even death. Hence, they are a strict dietary prohibition for pregnant and lactating women.

8. Digestive Issues

Many people who consume almonds experience stomach aches and diarrhea. These symptoms may occur immediately after consumption or several hours later. If you experience these symptoms, try taking probiotics or drinking plenty of water. You may also want to avoid eating nuts for a few days before trying again.

9. Heartburn

Heartburn occurs when acid refluxes back up into the esophagus. People who experience heartburn often feel burning sensations in their chest. To prevent heartburn, eat smaller portions of food at once and chew slowly. Avoid foods that cause indigestion, such as spicy foods, alcohol, caffeine, and fatty foods.

10. Bloating

Bloat is caused by gas buildup in the intestines. Gas builds up in the body due to poor digestion. Eating small meals throughout the day helps keep bloating under control. Try avoiding foods that cause gas, such as beans, broccoli, cauliflower, cabbage, Brussels sprouts, onions, garlic, and dairy products.

11. Nausea

Nausea is a feeling of sickness or discomfort in the stomach. It can be triggered by certain foods, medications, or changes in weather. Foods that trigger nausea include citrus fruits, tomatoes, cucumbers, peppers, chocolate, and coffee. Medications that can cause nausea include chemotherapy drugs and birth control pills. Changes in weather can make someone feel nauseous too (such as traveling in the hot summer in a car or plane).

Almonds are incredibly healthy, of course. But as is the case with any food, moderation is key.

How Many Almonds Can You Eat In A Day?

One ounce of almonds contains 23 kernels (1). There is no scientific data on how many almonds you can eat in a day to avoid the side effects. But anecdotal evidence suggests limiting your intake to 10 to 15 almonds a day. It is always better to soak almonds overnight to make fiber more bioavailable.

Almonds are loaded with many beneficial nutrients that can promote overall health. However, one must also note the side effects of almond consumption. Almonds may cause constipation, weight gain, and vitamin E overdose. Overconsumption may also cause kidney stones, and bitter almonds may increase toxin levels in the body. These nuts may also aggravate tree nut allergies, and their fiber may interfere with nutrient absorption. Hence, practice caution and consume almonds in moderation.

Frequently Asked Questions

What can you substitute almonds with?

You can replace almonds in your diet with hazelnuts, cashews, and pistachios (all unsalted). But remember, moderation is key. Do not consume more than a handful of nuts a day.

Are raw almonds safe to eat?

A: Yes, you can eat raw almonds. Keep in mind to wash them first and then dry them properly before storing.

Can you eat almonds on an empty stomach?

Yes, you can eat almonds on an empty stomach. Doing so helps accelerate your metabolism.

Can you drink the water of soaked almonds?

There is limited information on this. Hence, we recommend you not to drink the water of soaked almonds without consulting your doctor.

How do you know if almonds have gone bad?

If you open the container of almonds and sense a sour, chemical-like smell, your almonds have gone bad. These rancid almonds can taste bitter and must be thrown away.

You can try almonds that are beyond the best-buy date. Almonds can last up to a year if stored properly.

How long should almonds be soaked?

You can soak almonds overnight. With proper storage, soaked almonds can remain fresh for up to a week.


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Ravi Teja Tadimalla is an editor and a published author. He has been in the digital media field for over... more

Reda Elmardi

Reda Elmardi is a registered dietician, certified nutritionist, and certified strength and conditioning specialist trainer. He has more than 10... more