Goji berries: Health benefits and side effects
Many health claims have been made for goji berries, including maintaining a healthy heart and circulation, boosting the immune system, protecting against cancer and increasing longevity, yet the medical evidence to back up these claims is weak, according to the British Dietetic Association.
What is the goji berry?
The goji berry, also known as the wolfberry, is a member of the Solanaceae or nightshade family of plants. It’s a bright orange-red berry commonly grown in the north-central and western areas of China. The ripe berry is easily damaged during picking, so it’s common for them to be carefully dried to preserve them before export. In the UK they are commonly eaten as the dried fruit or as a component of fruit juice.
Goji berries have been used in traditional Chinese medicine to manage diabetes, high blood pressure, fever, age-related eye problems and fatigue associated with living at high altitudes. Goji berries are eaten raw, cooked, or dried (like raisins) and are used in herbal teas, juices, wines and medicines. The benefits of goji berries on human health are limited at the moment, although purified extracts from these berries seem to show some health benefits in animal research and a limited number of human studies.
What are the benefits of goji berries?
The blue-red colours found in goji berries, blueberries, acai berries, cranberries, strawberries, and cherries are natural anti-oxidants which may help protect the body against oxidative damage. In addition Goji berries contain complex starches called Lycium barbarum polysaccharides which may benefit the immune function, and may reduce fatigue associated with living at high altitude.
Antioxidants temper the destructive power of free radicals, substances occuring naturally in our body but if produced in excess accelerate cell damage and destruction. Chinese research has shown a standardised dose of goji berry extract given over a month-long trial helped boost levels of protective anti-oxidant liver enzymes, and reduced by-products of oxidative damage in the blood by almost 10%. It’s worth noting that although this research is promising, the test samples of goji berries were highly purified to contain a standard amount of the active ingredient, ‘Lycium barbarum polysaccharides’, which may not reflect the same content of goji berries bought at the healthfood shop or supermarket.
Goji berries also have compounds rich in vitamin A that may also confer health benefits. Vitamin A and its derivatives may protect against skin damage, help maintain night- vision, and benefit the immune system.
Some researchers suggest that goji berry extracts may improve mood, and protect against age-related diseases such as Alzheimer's, but there is no robust medical evidence to support these claims.
In summary, goji berries are a rich source of antioxidants with preliminary research showing some potential health benefits when taken in a standardised form - but there’s not enough sound evidence to recommend them solely for their health benefits.
Do goji berries have any dangerous side effects?
There are herb-drug interactions with goji berries. If you take warfarin (a blood thinner) you should avoid goji berries. Goji berries may also interact with diabetes and blood pressure medicines, so check with your pharmacist about possible interactions.
If you have pollen allergies you may want to stay away from this fruit. Case reports have linked goji berries consumption with skin photosensitivity, causing a skin rash on exposure to sunlight. They are also naturally rich in oxalate which may be a health issue in kidney problems.
Dietitian reviewed by Catherine Collins RD