Tart cherries are a popular nutritional food and supplement due to their high antioxidant content and anti-inflammatory properties. While generally considered safe, some potential side effects have been associated with consuming tart cherries. This article explores the scientific research on tart cherry side effects.
Tart cherries, also known as sour cherries or Prunus cerasus, are a type of cherry valued for their tangy taste and deep red color. Compared to the more common sweet cherry, tart cherries tend to be smaller, softer, and more acidic.
Tart cherries and their juice are rich in various nutrients and beneficial plant compounds, including (1):
- Anthocyanins: Pigments with antioxidant and anti-inflammatory properties
- Quercetin: An antioxidant that may help reduce inflammation
- Vitamin C: An essential antioxidant
- Melatonin: A hormone that regulates sleep-wake cycles
- Vitamin A: Important for immune function and vision
- Potassium: An essential mineral important for heart health
Research suggests that the high antioxidant content of tart cherries provides various health benefits, such as reduced muscle damage and soreness, decreased inflammation, and improved heart health markers like blood pressure and cholesterol (1, 2).
Given their nutritional benefits, tart cherries are a popular dietary addition, eaten fresh, dried, frozen, or juiced. Tart cherry juice concentrate, capsules, and powders are also available as supplements.
However, some people wonder if there are any potential downsides to regular tart cherry consumption. This article reviews the scientific research on tart cherry side effects.
Common mild side effects
For most people, eating tart cherries and taking tart cherry supplements in moderation is safe and well tolerated. However, some mild side effects have been associated with high intakes.
Eating a lot of tart cherries or drinking large amounts of tart cherry juice may lead to digestive issues in some people, including (3):
- Mild diarrhea
These effects are often dose-dependent, meaning the higher the intake, the more likely that digestive side effects may occur. Start with a low dose and increase slowly to assess your personal tolerance (4).
Additionally, tart cherries contain sorbitol, a type of sugar alcohol that can draw water into the intestine, potentially leading to diarrhea when eaten in excess (5).
Some research indicates that tart cherry juice may increase sleepiness and tiredness, potentially due to its natural melatonin content (6).
In a small study in 7 older adults, drinking 8 ounces (240 ml) of tart cherry juice twice per day for 2 weeks increased objective measures of sleepiness compared to a placebo juice (6).
Exercise caution when driving or operating heavy machinery after consuming tart cherry products, especially in high amounts.
Kidney stones and gout
People prone to kidney stones or gout may want to moderate their tart cherry intake.
Tart cherries contain modest amounts of oxalate, a compound that can contribute to kidney stone formation when consumed in high amounts (7, 8).
Those with a history of calcium oxalate kidney stones may want to keep their total dietary oxalate intake under 50–60 mg per day (9).
One cup (154 grams) of raw tart cherries provides around 10 mg of oxalate (10). Tart cherry juice concentrate would have higher oxalate levels in a per-cup (250-ml) serving.
While moderate intake is likely safe for most people, those prone to kidney stones should minimize very high tart cherry intakes to keep oxalate levels in check (9).
Gout is a form of inflammatory arthritis triggered by higher levels of uric acid in the blood. Uric acid can accumulate and form crystals in the joints, leading to swelling, redness, and intense pain (11).
Purine compounds found naturally in some foods can increase uric acid levels when consumed in excess. Tart cherries contain modest amounts of purines (12).
Thus, those with gout or hyperuricemia, a precursor to gout, should moderate tart cherry intake and avoid very high amounts that may trigger attacks (13).
However, emerging research indicates that the anthocyanins in tart cherries may help reduce blood uric acid levels and inflammation related to gout. In fact, several studies suggest tart cherries may be beneficial in managing gout symptoms (14, 15).
Still, it’s best for those prone to gout to discuss tart cherry intake with their healthcare provider.
Some potential interactions may occur between tart cherry products and certain medications. However, most research in this area is limited to animal studies.
Compounds in tart cherries may inhibit certain enzymes involved in drug metabolism. Consuming tart cherries could potentially increase the effectiveness and side effects of certain blood-thinning medications like warfarin (Coumadin) (16, 17).
Speak with your healthcare provider before combining tart cherry products with any blood-thinning medications.
Given their natural melatonin content, tart cherries may have additive sedative effects when combined with sedative medications like benzodiazepines (18).
Avoid pairing high doses of tart cherry supplements with sedatives without medical supervision.
A few animal studies suggest that compounds in tart cherries may reduce high blood sugar levels and increase insulin production (19, 20).
Therefore, it’s possible that tart cherry products may enhance the blood-sugar-lowering effects of diabetes medications. Monitor your blood sugar closely if combining tart cherries with diabetes drugs.
More research is needed on interactions between tart cherries and specific medications.
In rare cases, tart cherries or their components may cause side effects in sensitive individuals, including (3):
- Mouth sores
- Allergic reactions, such as hives, itching, or swelling
- Asthma symptoms
Discontinue use if any negative reactions occur.
Pregnancy and breastfeeding
Moderate consumption of tart cherries during pregnancy is likely safe. However, data on the effects of high supplemental doses is lacking (21).
Pregnant women should stick to food amounts of tart cherries and avoid large supplement doses, unless approved by a healthcare provider.
There are currently no studies on tart cherry supplements during breastfeeding. Nursing women are advised to err on the side of caution and limit intake to normal dietary quantities.
Typical supplemental doses of tart cherry products range from 500–1,500 mg per day for capsules or tablets and 4–16 ounces (120–480 ml) for juice concentrate (22).
The most common dose used in research studies is around 480 mg per day of tart cherry extract or powder (22).
When it comes to fresh or dried tart cherries, a 1-cup (155-gram) serving is considered a high dose. Regarding juice, 8 ounces (240 ml) is a commonly used serving size.
Assess your personal tolerance when determining your ideal dose. Start low with about 4–6 ounces (120–180 ml) of juice or 50–100 mg of supplements daily for a week before increasing.
Additionally, keep total dietary oxalate intake under 50–60 mg if you have a history of kidney stones.
When consumed in moderation, tart cherries are likely safe for most people and do not appear to pose any serious health risks.
Potential side effects may include digestive issues and sleepiness when taken in excess. Those prone to kidney stones or gout should moderate their intake.
Tart cherry supplements may interact with certain medications like blood thinners and sedatives. Individual sensitivity is also possible but rare.
Pregnant and breastfeeding women should stick to normal food amounts and avoid large supplemental doses unless approved by their healthcare provider.
Start with a low dose around 4–6 ounces (120–180 ml) of juice or 50–100 mg of capsules or powder daily and increase slowly to determine your tolerance.
When used properly, tart cherries can be safely enjoyed as part of a healthy, balanced diet by most people.
|Potential side effect||Main causes||Individuals at risk|
|Digestive distress||Excess fructose, sorbitol, and fiber from high intake||Sensitive individuals|
|Sleepiness||Melatonin content||Older adults, sedative medication users|
|Kidney stones||Modest oxalate content||Those prone to kidney stones|
|Gout attacks||Purine content||Those with gout|
|Medication interactions||Effects on drug metabolizing enzymes and additive effects||Blood thinner, diabetes, and sedative medication users|
|Allergic reactions||Sensitivity to compounds||Sensitive individuals|