Chia seeds can be part of a nutritious diet. But eating too many may increase the risk of gastrointestinal symptoms and choking. They can also interact with certain medications.

Chia seeds are a nutritious food derived from the Salvia hispanica plant. They’re often used in recipes like puddings, pancakes, smoothies, and parfaits.

Chia seeds contain many important nutrients that may help protect against inflammation, oxidative stress, and high blood pressure. These may include omega‐3 fatty acids, antioxidants, vitamins, minerals, and fiber.

However, while chia seeds can be a nutritious dietary addition for most, eating too many may cause some side effects.

This article examines the side effects of eating too many chia seeds.

The most common side effects related to eating too many chia seeds are digestive symptoms.

Chia seeds are a good source of fiber, with a 1-ounce (28-gram [g]) serving providing over 9 grams (g) of fiber.

Fiber is essential for your health, as it can help support bowel regularity, the beneficial bacteria in your gut, and blood sugar management, among other important roles.

However, eating too much fiber may cause gastrointestinal symptoms in some people, including:

This can also occur when a high fiber diet is paired with inadequate hydration, since water is essential to helping fiber pass through the digestive system.

Furthermore, if you have ulcerative colitis or Crohn’s disease, you may need to monitor your fiber intake and limit chia seeds during flare-ups. These are periods when symptoms reappear or are much more severe.

Fiber in chia seeds comprises 85% to 93% insoluble fiber, which is a type of fiber that doesn’t dissolve in water. It passes through your intestines undigested.

According to the Crohn’s and Colitis Foundation, consuming too much insoluble fiber may worsen gastrointestinal symptoms like diarrhea, bloating, and abdominal pain.

Chia seeds are very small, but they may increase your risk of choking if you eat too many at once or have difficulty swallowing.

When dry chia seeds are exposed to water, they swell and absorb around 12 times their weight in liquid. These properties are useful for cooking and baking, but they can potentially swell up and become lodged in the throat.

Some research also suggests that consuming dry chia seeds on their own may be a risk factor for choking.

According to a 2014 case study, a 39-year-old had a dangerous incident with chia seeds after eating a tablespoon of dry seeds and then drinking a glass of water. The seeds expanded in the person’s esophagus, causing a blockage that required emergency medical treatment to remove the blockage.

Before eating chia seeds, make sure to let them soak in water for 5 to 10 minutes.

Some people may experience an allergic reaction after eating chia seeds, but this is rare.

Some case reports found that people with allergies to sesame seeds, hazelnuts, and peanuts experienced an allergic reaction when eating chia seeds.

This may be due to cross-reactivity, a process in which proteins in the allergenic food are also present in chia seeds, therefore possibly triggering an allergic reaction.

Food allergy symptoms may include:

In severe cases, food allergies can even lead to anaphylaxis, a life threatening condition that may cause difficulty breathing, tightness in the throat and chest, and even fainting.

A 2019 review also reported two cases in which people with no known food allergies experienced allergy symptoms after consuming chia seeds. One person developed hand eczema symptoms, including dry, itchy skin plaques.

If you try chia seeds for the first time and experience any allergy symptoms, discontinue use immediately and speak with a healthcare professional.

Chia seeds are safe for most people, but you may want to limit your intake if you’re taking medications to manage certain health conditions.

For instance, research suggests that chia seeds may lower blood sugar levels. This could be due to the high amount of fiber, which slows the absorption of sugar in the blood and can decrease blood sugar levels.

In most cases, eating moderate amounts of chia seeds can help people with diabetes manage their blood sugar levels. But insulin dosages are personalized and carefully adjusted to prevent dips and spikes in blood sugar.

As such, eating an excessive amount of chia seeds might cause blood sugar levels to decrease, possibly leading to a medication dosage adjustment.

Chia seeds may also reduce blood pressure. This may be due to omega-3 fatty acids, which have been shown to work as a blood thinner and decrease blood pressure.

While some people with hypertension (high blood pressure) may find this desirable, eating too many chia seeds may enhance the activity of blood pressure medications, possibly leading to hypotension (low blood pressure).

Limited research supports the direct effects of eating chia seeds on these health conditions, but to prevent possible side effects, it’s best to speak with a healthcare professional before incorporating them into your diet.

Chia seeds contain a good amount of alpha-linolenic acid (ALA), a type of omega-3 fatty acid found primarily in plant foods.

Omega-3 fatty acids are an essential part of the diet and have been shown to support many aspects of health, including cognitive function and heart health.

Although omega-3 fatty acids are generally recognized as beneficial for health, some studies have found an association between ALA intake and prostate cancer.

A 2018 review in 47,885 people with a prostate found that ALA intake was associated with an increased risk of advanced prostate cancer over the course of 24 years.

However, this association was only found for the period before prostate-specific antigen (PSA) tests became part of regular health screenings. After this period, there was no link between ALA and prostate cancer.

The authors concluded that the associated difference between these two periods was significant, which indicates that PSA tests have greatly reduced the risk of developing advanced prostate cancer.

Further studies are needed to examine the possible relationship between ALA intake and prostate cancer.

Consider limiting your intake of chia seeds if you have an underlying health condition like a seed or peanut allergy, ulcerative colitis, Crohn’s disease, hypertension, or diabetes.

Yes, eating too many chia seeds may cause temporary digestive symptoms like abdominal pain, bloating, flatulence, diarrhea, and constipation.

Eating too many chia seeds may trigger symptoms of irritable bowel syndrome (IBS) in some people.

Eating 2 tablespoons of chia seeds daily is generally considered safe for most people.

The bottom line

Chia seeds are highly nutritious, versatile, and tasty foods that could be a healthy dietary addition for most.

But moderation is key, as eating too much may cause side effects, such as constipation and abdominal discomfort.

To help prevent side effects, start with 1 ounce (28 g) daily and assess your tolerance before slowly increasing your intake. Also, stay hydrated as you increase your fiber intake, and soak chia seeds for 5 to 10 minutes before eating them.

If you continue to experience negative symptoms after eating chia seeds, stop eating them and consult a healthcare professional.