5 Side Effects Of Eating Too Many Blueberries

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If you binge on blueberries, the high levels of resveratrol will stop the benefits of exercise. Your blood pressure and cholesterol won’t improve like they normally would. Resveratrol can also cause stomach problems and act like estrogen, which is harmful for hormone-sensitive conditions. A high intake should also be avoided by people who have bleeding disorders, surgery, or who take anticoagulants. The risk of bleeding will increase, which is life-threatening.

When it comes to fruits, you can’t go wrong with blueberries. All you need to do is wash and enjoy! You don’t even need to peel or prep them. Unsurprisingly, it can be tempting to binge on these delicious berries. They’re healthy, so it must be OK… right? Well, maybe not. Eating too many blueberries can have some adverse effects on your health.

5 Side Effects Of Eating Too Many Blueberries

Despite their antioxidants and benefits, overeating blueberries may work against you. Too much of a good thing isn’t always ideal. So before you gorge on blueberries, keep these five side effects in mind.

1. Affects Your Exercise Routine

Eating Too Many Blueberries will affect your exercise

Blueberries are teeming with resveratrol, a powerful antioxidant. This phytochemical gives blueberries their deep blue shade! Resveratrol can also benefit the heart since it expands blood vessels and reduces blood clots. But if you get too much? Your efforts from exercise will be hindered.

In fact, when you exercise, resveratrol can lower the maximum oxygen uptake by 45 percent. Even your blood pressure and cholesterol won’t decrease. And when all these things are goals of exercise, it pays to keep this in mind.1

2. Increased Bleeding

Avoid Blueberries if you have hemophilia

If you have a bleeding disorder like hemophilia, go easy on the blueberries. Both its resveratrol and vitamin E will enlarge blood vessels and amplify your risk for bleeding.2 The slowed blood clotting from these nutrients also won’t help. If you lose too much blood, it can be life-threatening. To avoid these side effects, eat blueberries in moderation.

This can also cause problems during surgery. It may encourage bleeding during and after, making it hard to fully heal. Other complications can also develop. So if you have a surgery coming up, don’t overeat blueberries least 2 weeks prior.3

3. Stomach Problems

Blueberries can cause uncomfortable intestinal side effects

Eating too many blueberries can also cause uncomfortable intestinal side effects. The high intake of resveratrol has been linked to nausea, diarrhea, pain, and gas. And while these side effects were mild, they can last for about four days.4 No, thank you!

4. Estrogen-Like Effect

Blueberries can effect your estrogen levels

Avoid going crazy with blueberries if you have hormone-sensitive conditions. Examples include endometriosis, uterine fibroids, or cancer of the breast, uterus, and ovaries. The resveratrol in blueberries has a similar effect to estrogen, so it may aggravate these conditions. After all, these conditions are already linked to high levels of this hormone.5

5. Drug Interactions

Blueberries can amplify your risk of bruising and bleeding

Are you taking anticoagulant or antiplatelet drugs? Overeating blueberries can be bad news. These drugs prevent blood clotting, but so does the resveratrol in blueberries. Together, these factors will amplify your risk of bruising and bleeding.

Examples of anticoagulants include warfarin and heparin. Antiplatelet drugs include clopidogrel and dipyridamole. But you should also be careful when taking over-the-counter medications like aspirin, naproxen, and ibuprofen. These drugs thin the blood, making blood loss more likely.6

Blueberries might be tasty, but you don’t need to go overboard. Even three servings a week can do a world of good.7 You should also try to switch it up and enjoy other berries and fruits. Remember, moderation is key!

References   [ + ]

1. Gliemann, Lasse, Jakob Friis Schmidt, Jesper Olesen, Rasmus Sjørup Biensø, Sebastian Louis Peronard, Simon Udsen Grandjean, Stefan Peter Mortensen et al. “Resveratrol blunts the positive effects of exercise training on cardiovascular health in aged men.” The Journal of physiology 591, no. 20 (2013): 5047-5059.
2. Vitamin E. University of Maryland Medical Center.
3, 5. Resveratrol. MedlinePlus.
4. Brown, Victoria A., Ketan R. Patel, Maria Viskaduraki, James A. Crowell, Marjorie Perloff, Tristan D. Booth, Grygoriy Vasilinin et al. “Repeat dose study of the cancer chemopreventive agent resveratrol in healthy volunteers: safety, pharmacokinetics, and effect on the insulin-like growth factor axis.” Cancer research 70, no. 22 (2010): 9003-9011.
6. Antioxidants. MedlinePlus.
7. Eat blueberries and strawberries three times per week. Harvard Medical School.