Moon drop grapes are a specially bred seedless variety of common grapes that have an interesting shape and sweet flavor. Because of how these grapes are grown, they are only available for a short period. But how are they different from regular grapes? Are they worth the hype?
What Are Moon Drop Grapes?
Moon drop grapes are a seedless variety of common grapes (Vitis vinifera) that are a cross between C22-121 and Beita Mouni varietals and supposedly have a distinct flavor and texture. Moon drop grapes grow over a short season and are available between August 20 and November 15, via a company called Grapery [1, 2].
What Do They Taste Like?
Moon drop grapes taste like normal grapes but are sweeter and much crunchier [1].
Nutrition
Like all grapes, moon drop grapes have several nutritious components. Though moon drop grapes have not been specifically studied, they contain many of the same compounds as common grapes, as they are the same species [3]:
- Dietary fiber
- Nitrogenous compounds such as proteins and amino acids. As the grapes mature, the concentration of these compounds increase
- Minerals such as iron, potassium, zinc, calcium, and manganese
- Phytonutrients such as phenols, polyphenols, anthocyanins, resveratrol, and flavonoids
- Vitamins such as vitamin A, vitamin C, vitamin K, and B vitamins such as B1 (thiamine), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), and B9 (folate)
Mechanism of Action
Moon drop grapes contain fiber, which has several effects in the gut. Viscous fiber can expand in the stomach and slow down the digestion process. It can also work to bulk up fecal matter and help relieve constipation [4].
Potential Benefits of Moon Drop Grapes
Moon drop grapes are safe to eat as food, but supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Insufficient Evidence For
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of moon drop grapes for any of the below-listed uses.
Furthermore, many of the purported benefits of moon drop grapes are based entirely on studies of their components (such as certain nutrients or, most often, resveratrol), rather than direct studies of the fruits themselves.
Moon drop grapes should never be used in place of something your doctor recommends or prescribes.
1) Constipation
All grapes contain fiber, which can prevent constipation and increase the movement of material in the digestive system [4].
In a clinical trial of 34 people, 4 tbsp/day of a natural laxative containing raisins was more effective than prescription laxatives at producing a normal frequency and consistency of bowel movements [5].
2) Bone Strength
Moon drop grapes have many nutrients that may be helpful for bone health, such as copper and manganese, which help in bone formation and strength. These nutrients prevent the development of conditions such as osteoporosis [6].
In a study of 66 people, 1,000 mg of resveratrol increased bone mineral density in the spine but not the hip. It also increased bone alkaline phosphatase levels, a marker of bone formation [7].
3) Heart Disease
Like other grapes, moon drop grape skins contain beneficial compounds. One of these compounds, resveratrol (a polyphenol), is thought to reduce the risk of cardiovascular disease [8, 9, 10].
In a study of 26 people with high blood pressure, red grape juice was able to reduce blood pressure for some people [11].
300 mg of resveratrol decreased LDL cholesterol levels in a study of 60 people [12].
In studies with animal models, resveratrol had a beneficial effect on high blood pressure, clogged arteries, stroke, heart disease, irregular heartbeat, and heart failure. These effects may be due to its antioxidant and anti-inflammatory properties. However much more studies are needed to confirm this theory [8, 9, 10].
4) Diabetes and Metabolic Syndrome
In a study of 24 people with metabolic syndrome, 500 mg trans-resveratrol decreased weight, fat mass, BMI, waist circumference, and total insulin secretion [13].
Treatment with 250 mg/day of resveratrol improved hemoglobin A1c, total cholesterol, and systolic blood pressure but not HDL or LDL cholesterol in a study of 62 people [14].
However, a study of 66 men found that resveratrol did not have any beneficial effects on metabolic syndrome. Surprisingly, 1,000 mg resveratrol actually increased total and LDL cholesterol and fructosamine levels (a marker for diabetes). Inflammatory status, sugar levels, blood pressure, and liver fat content were not improved with resveratrol treatment [15].
A study of 192 type 2 diabetes patients also found that resveratrol supplementation did not change any of the parameters measured, notably fasting glucose, insulin, hemoglobin A1c, weight, waist circumference, or blood pressure [16].
5) Non-Alcoholic Fatty Liver Disease
In a study of 60 people, 300 mg of resveratrol improved various aspects of non-alcoholic fatty liver disease, decreasing aspartate aminotransferase, glucose, and LDL cholesterol levels [12].
6) Alzheimer’s Disease
Resveratrol and other phytochemicals found in grapes are thought to have a protective effect against Alzheimer’s disease [17, 18].
Grape powder containing various phytochemicals like resveratrol prevented metabolic decline in brain regions associated with the development of Alzheimer’s disease in a DB-RCT with 10 people [19].
Although 500 – 1,000 mg/day of resveratrol seemed to have some effects on the brain, it did not alter markers of Alzheimer’s disease and also increased brain volume loss in a DB-RCT of 119 people. This loss in brain volume was not associated with any cognitive or functional declines [20].
Animal and Cellular Studies
The following studies were only conducted on animal models or cell lines.
7) Age-Related Eye Diseases
Several age-related eye conditions, such as cataracts, diabetic retinopathy (vision loss), glaucoma, and macular degeneration, are thought to be related to oxidative stress and inflammation [21].
Two review studies determined that resveratrol may potentially help age-related eye diseases due to its antioxidant and anti-inflammation effects. However, human trials need to be conducted [21, 22].
8) Asthma
In two animal studies, grape extracts were beneficial for asthma due to allergies. This effect may be due to its anti-inflammatory properties [23, 24].
Side Effects
Consumption of grapes in normal amounts has very few side effects and is generally very safe. Some commonly experienced side effects include [25, 20]:
- Abdominal cramping
- Bloating
- Diarrhea
- Flatulence
- Gas
- Nausea
- Weight loss
Drugs Interactions
The following listed drug interactions are not exhaustive. Please speak to your doctor if you are taking medication.
Grape juice may inhibit cyclosporine, an immunosuppressant. Common brands of cyclosporine include Neoral, Sandimmune, Gengraf, Restasis, and Restasis MultiDose [26, 27, 28].
Resveratrol inhibits enzymes (such as CYP3A, CYP3A4) that break down or deactivate many types of drugs and therefore can increase the potency of those drugs [26, 29, 27, 30].
Grapes and Pets
Grapes and raisins can be toxic to pets, especially dogs, with hundreds of reported cases of severe toxicity. If your pet has eaten even a single grape, call your veterinarian or pet poison control immediately [31].
Limitations and Caveats
While moon drop grapes should have similar effects and properties to grapes of the same species, Vitis vinifera, there have been no studies specifically conducted on this varietal. Therefore, the results from these studies can only be theoretically applied to moon drop grapes.
Some of the effects of moon drop grapes or of the polyphenol found in grape skin, resveratrol, have only been conducted in animal models or on cell lines.
Many of the studies directly contradicted other studies. For example, while many studies touted the antioxidant and anti-inflammatory effects of resveratrol, a DB-RCT of 20 people found that 500 mg of resveratrol had no antioxidant or anti-inflammatory effects [32, 33, 34].
Dosage
There is no standard dosage for grape consumption.
In the studies examining the effects of resveratrol, dosages as high as 1,000 mg/day were used. Such a dosage would be effectively impossible to obtain from eating grapes.
Forms of Supplementation
Moon drop grapes are available as fresh fruit in grocery stores.
Resveratrol, one of the main beneficial compounds in grapes, is available as a supplement in the form of capsules or powder.
