A compound found in apple peel has been found to increase muscle and brown fat in mice on a high-fat diet.
Mice exposed to ursolic acid burn more calories, have a reduced incidence of reduced obesity, pre-diabetes and fatty liver disease than mice not receiving the supplement.
The findings suggest ursolic acid reduces obesity and its associated health problems by increasing the amount of muscle and brown fat, two tissues recognised for their calorie-burning properties, a new study by University of Iowa found.
The study, which was published June 20 in the journal PLoS ONE, was led by Christopher Adams, M.D., Ph.D., UI associate professor of internal medicine and a Faculty Scholar at the Fraternal Order of Eagles Diabetes Research Center at the UI.
"From previous work, we knew that ursolic acid increases muscle mass and strength in healthy mice, which is important because it might suggest a potential therapy for muscle wasting," Adams says.
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"In this study, we tested ursolic acid in mice on a high-fat diet - a mouse model of obesity and metabolic syndrome. Once again, ursolic acid increased skeletal muscle. Interestingly, it also reduced obesity, pre-diabetes and fatty liver disease.
"Since muscle is very good at burning calories, the increased muscle in ursolic acid-treated mice may be sufficient to explain how ursolic acid reduces obesity. However, we were surprised to find that ursolic acid also increased brown fat, a fantastic calorie burner. This increase in brown fat may also help protect against obesity."
Until quite recently, researchers believed that only infants had brown fat, which then disappeared during childhood.
However, improved imaging techniques have shown that adults do retain a very small amount of the substance mostly in the neck and between the shoulder blades. Some studies have linked increased levels of brown fat with lower levels of obesity and healthier levels of blood sugar and blood lipid, leading to the suggestion that brown fat may be helpful in preventing obesity and diabetes.
The UI team, which also included Steven Kunkel, Christopher Elmore, Kale Bongers, Scott Ebert, Daniel Fox, Michael Dyle, and Steven Bullard, studied mice on a high-fat diet over a period of several weeks.
Half of the animals also received ursolic acid in their high-fat food. Interestingly, mice whose diet included ursolic acid actually ate more food than mice not getting the supplement, and there was no difference in activity between the two groups.
Despite this, the ursolic acid-treated mice gained less weight and their blood sugar level remained near normal. Ursolic acid-treated mice also failed to develop obesity-related fatty liver disease, a common and currently untreatable condition that affects about one in five American adults.
Further study showed that ursolic acid consumption increased skeletal muscle, increasing the animals' strength and endurance, and also boosted the amount of brown fat. Because both muscle and brown fat burn calories, the researchers investigated energy expenditure in the mice and showed that ursolic acid-fed mice burned more calories than mice that didn't get the supplement.
"Our study suggests that ursolic acid increases skeletal muscle and brown fat leading to increased calorie burning, which in turn protects against diet-induced obesity, pre-diabetes and fatty liver disease," Adams says.
"Brown fat is beneficial and people are trying to figure out ways to increase it. At this point, we don't know how ursolic acid increases brown fat, or if it increases brown fat in healthy mice. And, most importantly, we don't know if ursolic acid will benefit people. Our next step is to determine if ursolic acid can help patients."
The New Superfoods
Artichokes are a rich source of iron and antioxidants. The Jerusalem variety has the highest levels of iron, helping to beat fatigue, aid concentration and maintain a healthy metabolism.
Black garlic is aged for a month in a fermentation process under high heat (hence its darker colour) and tastes sweeter than normal garlic so it doesn't leave a pungent taste in your mouth. It contains twice as many antioxidants than traditional raw garlic and has high levels of S-Allycysteine, a natural compound that has been proven to help prevent cancer.
This blue-green algae is packed full of iron and vitamin B12, which are great for maintaining energy levels and fighting fatigue. This tiny aquatic plant is packed, ounce for ounce, with more Vitamin A than carrots and is a rich source of phytochemicals, which are said to help reduce menopausal symptoms and osteoporosis and reduce the risk of developing certain types of cancer.
Hemp seeds are an excellent source of omega 3 fatty acids, which help fight inflammation and joint pain, improve metabolism and keep the heart healthy. They also contain a more digestible form of protein than milk and eggs. Eat them raw in salads or grind them with a pestle and mortar and sprinkle them over baked foods or cereals. Hemp seeds can be also be found in an oil form which can be used for cooking or a salad dressing.
Kukicha Twig Tea
The 'twig tea' is made of the stems and stalk from the Kukicha plant and is a herbal remedy used for reducing bloated stomachs and boosting the immune system with its high levels of disease-beating antioxidants. Typically found in tea form, it is low in caffeine, which helps keep the blood pressure levels down.
Adzuki beans contain more protein and less fat than any other pulse. They also contain high levels of potassium which helps lower the risk of strokes and high blood pressure, fibre for good digestion and zinc, which protects the body from inflammation of the joints and helps maintain healthy blood sugar levels.
Although notoriously high in fat, this clarified butter used in Indian cooking is thought to improve memory, digestion and boost the immune system. Ghee is made by simmering unsalted butter in a pot until all the water has boiled. Ghee is the milk solids that has settled to the bottom of the pot and is best enjoyed in moderation.
Commonly used in Indian cuisine, fenugreek is used as both a herb and a spice and is said to be good for reducing cholesterol, improving the symptoms of diabetes and soothing menstrual cramps and menopausal symptoms.
This creamy-fleshed fruit, which is part of the cocoa family, is being billed as the new 'super fruit' with its high levels of antioxidants. It can found in health juices or in a pill. It is a rich source of vitamins B1, B2, B3, fatty acids and at least nine antioxidants (including Vitamins A and C). The fruit has a similar effect on the body as caffeine without the caffeine content, so it energises the body the natural way. You don't have to eat it to reap the benefits as it can be found in face and body creams too.
These tiny brown seeds are packed with omega 3 fatty acids, great for maintaining healthy energy levels. They are also said to help lower blood pressure and the risk of inflammation, as well as helping slow down premature ageing by reducing the risk of free-radical damage to the skin. Sprinkle Chia seeds on salads, include them in your dipping sauces or salad dressings, throw them in stews or heat them up until they go soft and gel-like and then use as a spread for sandwiches or include in baking recipes.