We all love grapes. They are not only delicious but also incredibly nutritious. These fruits are replete with vitamins and minerals and fiber – absolute essentials for healthy living.
But there’s a problem. You can eat too many of them. As they are tiny, you wouldn’t even know when you go overboard. The consequences of eating too many grapes are very unpleasant.
In one study, ingestion of grapes lead to acute renal failure in dogs (1). We aren’t sure if they would cause similar issues in humans. But research does highlight certain side effects of grapes that we must be aware of.
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How Can Grapes Cause Side Effects?
The size of grapes can be deceiving. They are small, so you might end up ingesting too many of them. One full cup (about 30 grapes) of grapes contains less than 105 calories (2). This is not much – unless you sit with a big bowl before a TV, and before you know it, the bowl is empty.
Eating large portions of grapes regularly can lead to weight gain. This is especially true if you don’t consciously watch what you eat every day.
Grapes also contain fiber, and consuming excess of it all of a sudden will cause problems – including constipation (3).
Most of the ill effects of grapes have to do with their excess intake. Though the side effects are not common, it is important you know about them.
What Are The Side Effects Of Grapes?
The salicylic acid in grapes can cause digestive problems. This happens if you overeat grapes. Eating too many grapes in a day can also lead to diarrhea. Weight gain over time is another possible side effect of excess intake of grapes.
1. May Cause Stomach Upset
Grapes contain salicylic acid, which may cause nausea, vomiting, and gastric discomfort in individuals (4). It can irritate your stomach as it causes damage to the gastric lining.
The seeds of grapes even caused appendicitis in some individuals (5). Undigested seeds or even the residue of fruits may also cause acute abdominal pain.
Grapes may also cause problems if you have irritable bowel syndrome. This is because they contain insoluble fiber, which stimulates the gastrointestinal tract (6). If you have IBS, ensure you do not eat them on an empty stomach.
If you have indigestion or some form of stomach upset, consuming ginger juice might help. Ginger also helps relieve nausea (7).
2. Can Result In Diarrhea
Foods high in sugar may cause diarrhea. Intake of foods high in sugar can send water into your intestines. This results in very loose stools. Grapes are rich in natural sugars, which can cause problems.
Even grape juice may cause diarrhea in susceptible individuals as it contains simple sugars (8).
Grapes can also cause traveler’s diarrhea. This is the form of diarrhea you contract when you visit a different place where the food or sanitary practices are different from where you live. Along with grapes, it is better to avoid other unpeelable fruits when you have traveler’s diarrhea (9).
Traveler’s diarrhea can be problematic as you are away from home. You can cut down the risk by taking an antacid medicine containing bismuth (like Pepto-Bismol) (10). You can take 1 tablet (262 mg) 4 times a day. Do check with your pharmacist or doctor for the ideal dosage.
Remember, this medication is not recommended for pregnant women and children under 3 years of age.
3. May Lead To Weight Gain
Eating too many grapes in one sitting can make the calories add up fast. This can negate the health benefits of grapes and even increase the risk of weight gain.
Also, you may want to reduce the intake of grapes as a snack. Otherwise, you will only be stopping yourself from hitting your weight loss goals. Grapes are lower in calories when compared to cookies and granola bars, but overeating them would defeat the purpose.
Prefer fresh grapes over canned varieties. Canned grapes contain twice as much sugar.
There is less direct research in this aspect. But given that grapes are small and delicious, we often tend to overeat them. Make grapes a part of your daily diet – but be wary of the portion sizes (8 to 10 grapes a day should do).
4. May Cause Complications During Pregnancy
This has much to do with the resveratrol in grapes, which is a powerful polyphenol. Resveratrol is also found in red wine. Though studies warn against consuming wine as a source of resveratrol, you may want to be wary of grapes too (11). Please check with your doctor as well.
In a study, resveratrol supplements were found to cause pancreatic problems in the developing fetus. The study doesn’t state anything against grapes – but it is better to be safe (12).
5. May Cause Choking In Kids
This is a prevalent problem. Uncut grapes may cause choking in kids – especially those between 6 to 12 months of age. This is the period when kids learn to chew and swallow food (13).
Uncut grapes are the problem. Ensure you give your toddler cut grapes to prevent choking.
The reasons grapes are one of the few foods that pose a high risk is their size and shape. A grape has near perfect dimensions to block a child’s airways.
But, God forbid, should your child choke, you must know what to do. The following pointers can help (14):
- If you can see the grape, try removing it with your fingers. Do not blindly poke fingers as you might end up pushing the grape further in. This may make things worse.
- If you cannot see the fruit and your child is silent or not coughing effectively, please call for help.
- If your child is conscious but still struggling, try giving back blows. You can do this by laying your child face down along your thighs. Support their head with your hand. Give about 5 sharp back blows with the heel of your hand in the middle of the back (between the shoulder blades).
6. Can Cause Allergies
Although grape allergy is rare, it can be problematic. A particular protein in grapes is found to cause allergies. It is called grape lipid transfer protein, and it was found to cause severe reactions in individuals (16).
Grapes can also cause anaphylaxis, which can be life-threatening. This allergy is characterized by hives and a feeling that your throat is closing (17). These symptoms can be more pronounced in people allergic to apples, peaches, cherries, and bananas, as these may also induce anaphylaxis (18).
Grapes may also cause salicylate allergy. There is less research on this, though. The symptoms of this allergy may include wheezing and trouble in breathing, nasal congestion, headaches, itching and rashes, stomach pain, and swelling of the hands and feet.
Salicylates are compounds found in most fruits and vegetables, including grapes.
Most grape allergies are not life-threatening, except for anaphylaxis. Anaphylaxis occurs by the release of histamine and other chemicals in the body. This results in leaky blood vessels, eventually leading to the swelling of tissues in the mouth and airways (and dangerously low levels of blood pressure too).
The best-known treatment for anaphylaxis is epinephrine administration. Epinephrine is a chemical in the body that elevates heart rate and blood pressure.
You can purchase epinephrine from your nearest pharmacy as a pre-filled syringe. It can be immediately injected into the thigh muscle once the symptoms of anaphylaxis are recognized (19).
If you are susceptible to such allergic reactions, keeping an epinephrine injection handy can help.
7. May Aggravate Kidney Problems
There is very less research on the ill effects grapes can have on humans. But they have had severe effects on animals.
Studies have shown acute renal failure in dogs post the ingestion of grapes. After consuming grapes, dogs were reported to have vomited. They also had experienced anorexia (loss of appetite), lethargy, and diarrhea (20).
A report by the National Institute of Diabetes and Digestive and Kidney Diseases suggests individuals with advanced chronic kidney disease limit their intake of certain foods, including grapes (21).
Though no studies have directly linked grapes to adverse kidney effects in humans, we suggest you exercise caution. If you have any form of kidney ailment, please keep away from grapes. Talk to your doctor too.
As discussed, grapes are generally safe. They are incredibly nutritious too. But it is important to know the ill effects they can cause. These fruits can also interact with certain drugs. If you are on any form of medication, you should be careful.
Do Grapes Interact With Any Drugs?
Grapes can interact with the following drugs:
This list includes drugs that are broken by the liver and those that slow down blood clotting. If you are taking any such drugs, you should check with your doctor before consuming grapes.
Grapes make for a healthy addition to our regular diet. They are rich in vital nutrients. Their appealing taste makes it easier for us to include them in our diets.
But the downside is their size – they are too small to be eaten in limited portions. You might eat too many of them, and that can defeat the purpose of incorporating them into your routine.
Keep a check on your portions. That way, you can enjoy the goodness of grapes without any apprehensions.
Do you have grapes every day? Do you simply pop them in or include them in a special recipe? Share your thoughts with us in the box below.
Frequently Asked Questions
How many grapes can you eat in a day?
About 32 grapes can be considered as one serving. Eating one serving is okay if you are already on a healthy diet and physically active. But otherwise, we recommended you stick to 8 to 10 grapes a day.
Can you eat grapes in the night?
Yes, you can. In fact, eating grapes at night might promote better sleep. Grapes contain melatonin, the sleep hormone (22).
- “Acute renal failure in dogs after the…” Journal of Veterinary Internal Medicine, US National Library of Medicine.
- “Grapes, American type…” United States Department of Agriculture, National Nutrient Database.
- “Stopping or reducing dietary fiber intake reduces…” World Journal of Gastroenterology, US National Library of Medicine.
- “Salicylic acid” Toxicology Data Network.
- “Can fruit seeds and undigested plant…” Asian Pacific Journal of Tropical Biomedicine, US National Library of Medicine.
- “Tips for relieving irritable bowel syndrome” University of North Carolina, Wilmington.
- “Natural remedies for gastrointestinal problems…” Acupuncture and Massage College.
- “Diarrhea” Rogers State University.
- “Prevention and Self-Treatment of Traveler’s Diarrhea” Clinical Microbiology Reviews, US National Library of Medicine.
- “Managing traveler’s diarrhea while…” Centers for Disease Control and Prevention.
- “Resveratrol” Oregon State University.
- “Resveratrol supplements cause pancreatic problems…” Oregon Health & Science University.
- “Choking hazards” Centers for Disease Control and Prevention.
- “How to help a choking child” National Health Service.
- “Learn first aid for a child who is choking” British Red Cross.
- “Severe immediate allergic reactions to grapes…” International Archives of Allergy and Immunology, US National Library of Medicine.
- “Anaphylactic reactions to cherries, strawberries, and grapes” American Academy of Allergy Asthma & Immunology.
- “Grape anaphylaxis: a study of 11 adult…” Allergy and asthma proceedings, US National Library of Medicine.
- “Another option for life-threatening…” Harvard Medical School.
- “Acute renal failure in dogs after the ingestion…” Journal of Veterinary Internal Medicine, US National Library of Medicine.
- “Heart disease & kidney disease” National Institute of Diabetes and Digestive and Kidney Diseases.
- “Melatonin; from pineal gland to…” CiteSeerX Journals.
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