Introduction
Metabolism, metabolic health and metabolic syndrome
Metabolism refers to the chemical processes that occur within cells to produce energy and maintain life.1 On the other hand, metabolic health is defined as having blood sugar, waist circumference, blood pressure, cholesterol, and triglycerides all within a healthy range. The opposite of metabolic health is metabolic syndrome, defined as a cluster of conditions, increasing the risk of metabolic disorders such as heart disease, stroke, and type 2 diabetes.2 Metabolic syndrome causes increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels.3
How do grapes contribute to metabolic health?
Grapes are an excellent source of vitamins, minerals, and antioxidants. They also contain excess water, which keeps the body hydrated. health.4 Grapes possess the following health benefits:
- Antioxidant properties
- Anti-inflammatory effects
- Modulation of gut-microbiota,
- Anti-obesity effects
- Cardioprotective effects
- Hepatoprotective effects
- Antidiabetic properties
- Anticancer potential5
Nutritional profile of grapes
Grapes are packed with both major and minor nutrients, along with various phytochemicals that contribute to their health benefits.
- Major nutrients
- Carbohydrates
- Fibre
- Minor nutrients
- Vitamins (e.g., Vitamin C and K)
- Minerals (e.g., Potassium)
- Phytochemicals
- Polyphenols (e.g., resveratrol)
- Flavonoids
These nutrients along with their amounts are mentioned below:
- Water (82%)
- Carbohydrates (12–18%)
- Proteins (0.5– 0.6%)
- Fat (0.3–0.4%)
- Potassium (0.1–0.2%)
- Vitamin C (0.01–0.02%)
- Vitamin A (0.001–0.0015%)
- Calcium (0.01–0.02%)
- Phosphorus (0.08–0.01%)
- Boron6
Grapes health benefits
- Regulation of blood sugar levels
Grapes have a low glycemic index, meaning they do not spike blood sugar levels. Nutrients in grapes, such as oleanolic acid and flavonoids, have been shown to decrease blood glucose levels and improve insulin sensitivity, which helps regulate blood sugar.4
Oleanolic acid and oleanolic aldehydes present in the outer grape skin act as insulin secretagogues. Studies have found that flavonoids and epicatechin isolated from grapes help in beta-cell regeneration and improve chemically induced diabetes in animals.6
- Improved cardiovascular health
Grapes contain very little sodium and therefore help to control blood pressure. Grapes also contain potassium, which helps in balancing blood pressure. Studies have found an association between low potassium intake and increased blood pressure.
Resveratrol, a major component of grapes also helps protect against heart disease. Studies have shown that a diet rich in potassium relative to sodium can reduce the risk of heart disease.4
- Lowers Cholesterol levels
- LDL reduction
- HDL improvement
Grapes are high in fiber, making them effective in managing cholesterol levels. Research indicates that consuming red grapes can lower total cholesterol and LDL ("bad") cholesterol, while also potentially improving HDL ("good") cholesterol levels..4
- Antioxidant effect
Oxidative stress is associated with various health problems. Resveratrol, found in grapes possesses potent antioxidant properties. Moreover, grapes are good sources of phytochemicals like gallic acid, catechin, and epicatechin used for the production of antioxidative dietary supplements. Another component in grapes is anthocyanins, belonging to the flavonoid family and various studies have shown that anthocyanins have a wide variety of biological activities, including antioxidant activity.6
- Improves bone health
Calcium and potassium, found in grapes help maintain strong bones. Although more research is needed, the nutrients in grapes show promise in supporting bone health.4
- Helps immune system
Grapes are a great source of vitamin C, which can help the immune system fight against bacterial and viral infections such as yeast infections.4
- Weight Management
Obesity is a common and chronic metabolic disease characterized by excessive accumulation of fat and abnormal adipose distribution in the body. This could be due to multiple factors, such as a high-calorie diet, insufficient exercise, a sedentary lifestyle, and genetic inheritance. Obesity is a hallmark of many diseases, such as diabetes mellitus, cardiovascular disease, and cancer, and has become a global public health concern. Growing evidence has revealed grape extract's antiobesity activity with its possible mechanism. Animal studies revealed that grape seed flour helps in managing weight and improves lipid profile5
- Hepatoprotective Activity
Some studies have shown that nutrients present in grapes are useful in the prevention and treatment of non-alcoholic fatty liver disease (NAFLD).
For instance, a study revealed the following hepatoprotective health benefits
- Decreased fat accumulation,
- Decreased steatosis in the liver,
- Improved liver function and blood lipids and
- Regulated lipid metabolism.
An increasing number of studies have reported that grapes can protect the liver from chemically induced hepatotoxicity and hepatic damage caused by toxic organic substances, heavy metals, and some drugs.5
- Prevents cancer
Free radicals are molecules that can damage cells and may lead to cancer. Grapes are rich in antioxidants that scavenge these free radicals and improve overall health. Antioxidants reduce oxidative stress caused by these free radicals and help reduce the risk of cancer.
Resveratrol protects against cancer by reducing inflammation and blocking the growth of cancer cells. Grapes also contain catechins, quercetin, and anthocyanins which may be a powerful combination against cancer.4
- Improved brain health
Resveratrol, a powerful antioxidant, helps reduce oxidative stress, which may lower the risk of brain disorders like Parkinson’s and Alzheimer’s diseases. Although a study shows the potential of antioxidants when it comes to preventing cognitive disorders, there is still a need for research on humans to truly understand their beneficial effects.4
- Improvement in Gut Health
Grapes contain a high content of insoluble fiber, making them an excellent prebiotic candidate. This fibre helps restore intestinal microbiota, supporting gut health. Various studies have shown that fruits high in polyphenols such as grapes can have prebiotic effects, leading to changes in gut microbiota composition.7 8
Allergic reactions to grapes
Hypersensitivity to grapes can develop late in life causing a near-fatal anaphylaxis.9 There have been five major allergens isolated from grapes, and they include
- Lipid-transfer protein,
- Profilin,
- Thaumatin,
- Endochitinase, and
- Glucanase.
Summary
Metabolism involves all the chemical reactions in the body that provide energy and sustain life. Metabolic health is maintained by keeping blood sugar, waist circumference, blood pressure, cholesterol, and triglycerides within healthy ranges. Grapes, rich in vitamins, minerals, and antioxidants, offer numerous health benefits. They regulate blood sugar, enhance insulin sensitivity, and support cardiovascular health by lowering blood pressure and cholesterol. Antioxidant properties of grapes, combat oxidative stress and may prevent cancer and improve brain health. Additionally, grapes aid in weight management, improve liver function and support bone health and the immune system. Grapes also promote gut health through their prebiotic effect.
Frequently asked questions
What are the key benefits of consuming grapes for metabolic health?
Grapes offer numerous benefits for metabolic health, including blood sugar regulation, cardiovascular health, cholesterol management, antioxidant properties, and weight management. The nutrients and bioactive compounds in grapes, such as polyphenols and flavonoids, help improve insulin sensitivity, lower blood pressure, reduce LDL cholesterol, and combat oxidative stress, thereby supporting overall metabolic health.
Do grapes help regulate blood sugar levels?
Grapes have a low glycemic index, which means they do not cause significant spikes in blood sugar levels. Compounds in grapes, like oleanolic acid and flavonoids, enhance insulin sensitivity and lower blood sugar levels. Grape seed extract and other components also aid in improving insulin function and reducing glycosylated haemoglobin levels.
Can grapes aid in weight management?
Yes, grapes can aid in weight management. The polyphenols and fibre in grapes promote satiety, reducing overall calorie intake. Grape seed flour has been shown to enhance thermogenesis in brown adipose tissue and increase energy expenditure, which can help in managing body weight and improving lipid profiles.
Are there any potential allergic reactions to grapes?
Yes, some individuals may develop allergies to grapes, which can cause severe reactions such as anaphylaxis. Allergens in grapes include lipid-transfer proteins, profilin, thaumatin, endochitinase, and glucanase. Those with known food allergies need to be cautious when consuming grapes.
References
- Sánchez López de Nava A, Raja A. Physiology, Metabolism. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 [cited 2024 May 14]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK546690/.
- Araújo J, Cai J, Stevens J. Prevalence of Optimal Metabolic Health in American Adults: National Health and Nutrition Examination Survey 2009–2016. Metabolic Syndrome and Related Disorders [Internet]. 2019 [cited 2024 May 14]; 17(1):46–52. Available from: https://www.liebertpub.com/doi/10.1089/met.2018.0105.
- Metabolic syndrome: Increased risk of cardiovascular disease, diabetes-Metabolic syndrome - Symptoms & causes. Mayo Clinic [Internet]. [cited 2024 May 14]. Available from: https://www.mayoclinic.org/diseases-conditions/metabolic-syndrome/symptoms-causes/syc-20351916.
- 10 Health Benefits of Grapes. Cleveland Clinic [Internet]. [cited 2024 May 14]. Available from: https://health.clevelandclinic.org/health-benefits-of-grapes.
- Zhou D-D, Li J, Xiong R-G, Saimaiti A, Huang S-Y, Wu S-X, et al. Bioactive Compounds, Health Benefits and Food Applications of Grape. Foods [Internet]. 2022 [cited 2024 May 14]; 11(18):2755. Available from: https://www.mdpi.com/2304-8158/11/18/2755.
- Yadav M, Jain S, Bhardwaj A, Nagpal R, Puniya M, Tomar R, et al. Biological and medicinal properties of grapes and their bioactive constituents: an update. J Med Food. 2009; 12(3):473–84.
- Oliver L, Ramió-Pujol S, Amoedo J, Malagón M, Serrano M, Bahí A, et al. A Novel Grape-Derived Prebiotic Selectively Enhances Abundance and Metabolic Activity of Butyrate-Producing Bacteria in Faecal Samples. Front Microbiol [Internet]. 2021 [cited 2024 May 17]; 12:639948. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021714/.
- Yang J, Kurnia P, Henning SM, Lee R, Huang J, Garcia MC, et al. Effect of Standardized Grape Powder Consumption on the Gut Microbiome of Healthy Subjects: A Pilot Study. Nutrients [Internet]. 2021 [cited 2024 May 17]; 13(11):3965. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619073/.
- Vaswani SK, Chang BW, Carey RN, Hamilton RG. Adult onset grape hypersensitivity causing life-threatening anaphylaxis. Annals of Allergy, Asthma & Immunology [Internet]. 1999 [cited 2024 May 17]; 83(1):25–6. Available from: https://www.sciencedirect.com/science/article/pii/S1081120610635089.