Nutrients found in lemon zest, specifically polyphenols, can help improve insulin resistance.
Lemon zest is often used as garnish or to add a hint of flavor, but recent chatter has included lemon zest in discussions about diabetes control. A key ingredient found in lemon peels is polyphenols, which plays a major role in minimizing insulin resistance. An increase in insulin resistance leads to less responsiveness from the insulin hormone, resulting in uncontrolled levels of blood sugar. However, polyphenols has the ability to suppress the accumulation of fat in the abdominal area. In addition, the presence of naringin and hesperidin, bioflavonoids, function as dietary antioxidants, which have been shown in mice studies to prevent the progression of hyperglycemia. They do this by increasing hepatic glycolysis and glycogen concentration, while lowering hepatic gluconeogenesis.
While lemon zest may contain key ingredients in helping one manage their blood glucose levels, the magic lies in the peel. Similar claims have also been made for orange peels. A deeper evaluation of the skin contents shows that key ingredients, flavanones, are found in all citrus peels. Since the peel is separated into different layers, similar to the human skin, the amount of flavones in each layer also varies. The white part of the skin, the albedo, has been shown to contain a larger amount of flavones compared to other layers of the peel.
In addition to controlling blood glucose, the antioxidant properties of the flavones have been linked to the management of radical damage and inflammation, both of which are prevalent in type 2 diabetes. Glycation, the process of binding a sugar molecule, produces end products known as glycation end products (AGEs). Accumulations of AGEs result in browning, or increased amounts of inflammation and free radical damage throughout the body. Furthermore, increased amounts of AGEs can cause blood vessels to lose flexibility, which will lead to other adverse effects.
Lemon peels also contain vitamins such as vitamin C, vitamin, beta carotene, folate, calcium, magnesium, and potassium. Vitamin C in conjunction with calcium helps with bone health and the prevention of osteoporosis, rheumatoid arthritis, inflammatory polyarthritis, and other bone conditions. Vitamin C also serves a pivotal role in minimizing free radical damage. Antioxidant properties have been found in vitamin C; hence, the deficiencies of this vitamin in patients with diabetes result in higher inflammation. Along with the flavanones, vitamin C also helps minimize insulin resistance.
Fiber is another ingredient found in lemon peels. Studies have shown that higher fiber intake assists with digestion and elimination, lower blood pressure, and lowering of cholesterol. Soluble fiber is the main one that is found in lemon peels. Different from insoluble fiber, soluble fiber dissolves in water and forms a gel-like substance. The substance inhibits the breakdown of carbohydrates and the absorption of fat. Therefore, soluble fiber assists in managing diabetes by limiting the amount of carbohydrate that is broken down from food, resulting in a smaller amount of sugar in the blood. Compounds such as salvestrol Q40 and limonese found in lemon peels contain anti-carcinogenic properties.
Another common condition found in patients with diabetes is increased cholesterol. Patients with diabetes who have elevated cholesterol are at a significantly higher risk of having a stroke, which is reflective of a higher ASCVD score. Polyphenol flavonoids found in lemon zest also help lower LDL cholesterol, which will help in minimizing high blood pressure and other heart diseases.
While there are many benefits of lemon peel for diabetes, improper usage can also result in side effects. Lemons can cause heartburn and tooth erosions due to their acidity. Lemons are also diuretics; therefore, increased consumption may deplete the body of water. As a result, consumption in moderation is recommended. Studies have also shown that most of the key ingredients are found in the peel in itself and the actual meaty parts of the fruit are devoid of those impactful ingredients.
- Sprinkling lemon zest has been found to help control carbohydrate intake and lowering of cholesterol.
- Most of the key ingredients are in the skin and not the meat parts.
Researched and prepared by Jimmy Tran, Doctor of Pharmacy Candidate LECOM College of Pharmacy reviewed by Dave Joffe, BSPharm, CDE
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