The health benefits of goji berries
Goji berries are bright red fruits which originated in China. They can also be referred to as a wolfberry, and are extremely delicate with a sweet taste. In western societies, the berries are often eaten as a dried fruit or as part of a fruit-juice mix.
They are thought to have many benefits to the human body, and have been used in Chinese medicine for over 6000 years. It is true that the berries do have many properties which may make them good for improving health, and the evidence is discussed below.
100g of goji berries contains 83 calories. They are high in fibre (containing 32% of the RDA for an individual with a daily consumption of 2000 calories), and are an extremely rich source of Vitamin A and Vitamin C. They are also high in Iron, Calcium, Riboflavin, Potassium, Zinc, Copper and Selenium.
Furthermore, they have absolutely no saturated fat and very little sodium. Surprisingly, they also contain 11g protein, which is very high for a fruit. These berries have a much greater abundance of nutrients than many other fruits and vegetables, meaning they may be one of the healthiest fruit choices.
Below is a list of each nutrient contained within 100g goji berries, and what each nutrient can do for your health:
Vitamin A, also known as Retinol (180%)
Goji berries are one of the richest sources of Vitamin A on the planet. This essential nutrient is usually found in dairy products and it is unusual to have so much Vitamin A in such a small amount of fruit.
It is very important that the body gets enough Vitamin A in order to ensure that the immune system is effective in fighting diseases. It also helps with vision, particularly in dim light, and helps keep skin healthy.
Copper is a trace element which helps to produce red and white blood cells. Red blood cells are important for carrying oxygen to all areas of the body, which is necessary for cells to function. White blood cells contain antibodies which fight off disease and infection.
Copper also triggers the release of iron, another element which is needed to create haemoglobin, the substance which allows red blood cells to transport oxygen. Copper deficiency can cause impaired neurological function and growth, and so it is thought that increased copper in the diet can prevent these problems.
Selenium is a less well-known nutrient than some others, but is equally important. It is a trace element, without which we would have less defence against infection and damage to cells and tissue. Selenium is also thought to have a role in reproduction, and research has suggested that it can even help to reduce the risk of prostate cancer.
Geybels et al (2014) assessed selenium levels from toenail clippings of 1865 participants, and found that higher levels of selenium were inversely associated with prostate cancer risk; in other words, more selenium meant a lowered risk of cancer.
Riboflavin is found in many breakfast cereals, but it is less well associated with fruit. Goji berries are an excellent source of this vitamin (also known as Vitamin B2), which is important for keeping eyes, skin and the nervous system healthy.
It also helps the body to release energy from the food we eat, meaning that the body stores less food as fat. Furthermore, it plays a role in the production of red blood cells.
As mentioned above, iron helps to create haemoglobin, which is necessary in order for red blood cells to transport oxygen around the body. Without haemoglobin, muscles would not be able to work, organs would fail, brain damage can occur and the body can die.
Therefore, it is vital that enough iron is found in the diet in order to sustain healthy oxygen transportation. A deficiency in iron is known as anaemia, and is characterised by dizziness, tiredness, coldness, pale skin and a general feeling of being unwell.
Because goji berries contain 50% RDA iron, they are an excellent addition to the diet of anybody who has anaemia, particularly vegetarian people (as red meat is the most abundant source of iron in the human diet).
Dietary fibre (32%)
Fibre comes in two forms; soluble and insoluble. Soluble fibre dissolves in the body and is useful for reducing the amount of cholesterol in the blood and for minimising constipation by softening stool. Furthermore, it feeds the good bacteria in the gut which can help to prevent digestive problems.
Insoluble fibre does not get absorbed by the body, and instead helps to create bulky stool which moves through the digestive system easily. It also helps to slow down digestion, which is important for allowing the body to process the nutrients from food at a steady rate. Goji berries contain a greater amount of soluble fibre than insoluble fibre.
Vitamin C (32%)
This is usually a vitamin associated with orange fruits and vegetables, but goji berries are also an excellent source. Vitamin C is very important for a variety of functions, including keeping cells healthy and protected from damage, maintaining connective tissues which allow other tissues and organs to be supported, and it is very important in wound healing.
Scurvy is the disease characterised by a vitamin C deficiency, and it results in muscle and joint pain, tiredness, swelling and bleeding in the gums, and red dots on the skin.
Potassium is a mineral which helps to control the balance of fluids in the body. An imbalance of potassium, where there is too much or too little fluid in the body, can result in a condition known as hypokalemia (too little) or hyperkalemia (too much).
Both conditions are characterised by muscle weakness, fatigue and heart arrhythmias. This leads on to the second role of potassium, as a nutrient which ensures that the heart functions correctly. It counteracts the effects of sodium on increasing blood pressure, and having the correct ratio of potassium and sodium is important for ensuring that the heart functions correctly.
Goji berries have a very high amount of protein compared to other fruits. Protein is very important for a wide variety of bodily functions. It provides energy for the body to use, but also has a large role in the creation and reparation of bodily tissues including skin and muscles.
It is also important for making enzymes, hormones and other chemicals in the body which are needed to trigger certain bodily processes to occur or stop.
Zinc is a trace element which, like protein, helps to make new cells and enzymes. It also helps the body to process carbohydrates, fats and proteins into energy (which can prevent weight gain) and it plays a role in wound healing.
Mostly found in dairy products, calcium is very important for keeping bones strong and healthy. What is less well known is that it also helps to regulate unconscious muscular contractions, such as the heart beat. Furthermore, it helps to ensure that blood clots properly.
Abnormal blood clotting can lead to a condition called thrombosis, which kills nearly 1 million Americans every year, and so it is very important that the body has enough of this essential mineral.
The Benefits of Eating Goji Berries
Alongside the numerous nutrients contained within goji berries, they have a variety of specific health benefits:
- Fights against prostate cancer
- Prevents Heart Disease
- Supports Eye Health
- Improves Mental Wellbeing and Cognitive Performance
- Improving the Immune System
Can help to fight prostate cancer
Prostate cancer is the second most common type of cancer in American men, with skin cancer being the first (American Cancer Society, 2015). Not only that, but it is also the second biggest killer of all cancers in American men, following lung cancer.
The ACS estimates that in 2015, over 27,000 men will die from prostate cancer, and over 220,000 will be newly diagnosed. It is a serious health problem for men all over the world, but there are certain dietary changes which can improve prognosis.
Oxidative stress is essentially a by-product of necessary processes where cells in the body react with oxygen. Oxygen is needed to create energy in the body; specifically, to create a molecule called ATP which we need in order to breathe.
However, when the cells use oxygen to produce this molecule, free radicals are also produced. Free radicals are molecules which are missing an electron and as such are very reactive and unstable.
They can do a massive amount of damage in the body as they seek to fill the gap and restabilize, because they can pair with the wrong substances (such as proteins, lipids and even DNA) which can disrupt the function of these substances.
Free radicals can also be created purposefully by the body to fight off certain bacteria, and they are also produced when the body interacts with environmental factors like UV radiation, pollution and cigarette smoke. The amount of free radicals in the body increases with age.
Cells can protect themselves against free radicals by identifying when they have been paired with by too many free radicals, and ‘self-destructing’ to prevent more damage being done. Free radicals, however, sometimes attack these defence mechanisms, making them go haywire.
This can result in massive cellular death which cannot be recovered from. Free radicals can also damage DNA, which causes cells to mutate. When this occurs in abundance, cancer can form.
Despite the damage free radicals can cause, it is possible to prevent and even reverse the damage by consuming foods high in antioxidants. There is an extremely compelling evidence-base for soft, red-skinned berries having anti-cancer properties (Seeram, 2008) and it may be due to the phytochemicals which cause the notable red pigment in the skin of the berries.
These phytochemicals, which include antioxidant filled polyphenols, are able to reduce oxidative stress and inflammation and repair any damage which has occurred.
Research by Luo et al (2009) investigated the impact of LBPs (a constituent of the goji berry) on human prostate cancer cells. They performed both in vitro (within the glass) and in vivo (within the living) studies, and found that the LBPs can significantly inhibit both tumour volume and tumour weight.
This suggests that they are a very effective way to fight prostate cancer cells, and this may partly be due to their antioxidant effects.
Prevent Heart Disease
Cardiovascular disease (CVD) is the biggest killer in the United States (CDC, 2013), and in the United Kingdom, causing more than a quarter of all deaths (British Heart Foundation, 2014). CVD is a general term for any disease of the heart and blood vessels.
There are two main causes of CVD; a blood clot reducing blood flow to the heart, brain or body (thrombosis), or a narrowing of the arteries due to fat build-up (atherosclerosis).
A number of risk factors can increase the chances of an individual developing CVD, including excessive body weight, diabetes, smoking, high blood pressure, and a genetic predisposition to heart disease.
Fortunately, it is also possible to prevent CVD. One of the main ways of decreasing CVD risk is to make dietary changes which reduce the amount of salt and saturated fat consumed. Increasing fruit and vegetable consumption is also beneficial.
Adding goji berries to the diet can be particularly useful for preventing heart disease, as they have very particular properties which help to reduce a number of CVD precursors.
A review of the efficacy of goji berries for a variety of health problems was conducted by Amagase et al (2011). They found that in a number of rat models, hypertension (high blood pressure) was prevented significantly following treatment using LBPs (the same constituents used to reduce the size of cancer cells).
Furthermore, research by Jing et al (2009) showed that LBP treatment can significantly reduce the concentration of fasting blood glucose, blood cholesterol and triglycerides in diabetic rats (all of which are precursors to atherosclerosis).
These studies have been supported by many others. For instance, Pai et al (2013) fed rats a high-cholesterol diet for 45 days. It was found that when rats were treated with LBP they showed a significant reduction in total cholesterol and triglycerides, compared to rats without LBP treatment.
Supports Eye Health
Age-Related Macular Degeneration (ARMD) is a degeneration of vision due to damage to the macular, a part of the eye responsible for central vision, most coloured vision and fine detail in visual images (Macular Society).
Ageing is the main cause of the disease as cells lose their ability to regenerate as they get older, but there are other factors including free radical damage, alcohol consumption and smoking.
Consuming a diet high in antioxidants can significantly reduce the amount of cell damage caused by free radicals, and as such can prevent ARMD or delay its onset.
Goji berries, as previously mentioned, are very high in antioxidants. This high antioxidant capacity has been investigated alongside goji berry properties for fighting ARMD in a research study by Bucheli et al (2011).
150 healthy elderly adults were given either a milk-based goji berry formulation or a placebo for 90 days. They were also given eye examinations to assess macular health, and blood tests examined antioxidant capacity.
After 90 days, markers of macular degeneration were significantly greater in the placebo group compared to the beginning of the study. In the goji-berry group, however, degeneration markers remained stable over the course of the study.
Furthermore, the goji-berry group also showed a 57% increase in blood antioxidant levels whereas the placebo group showed no increase. Due to the increase in antioxidants and the lack of macular degeneration, this research suggests that the antioxidants in goji berries may help to counteract the cell damage and death which can lead to ARMD.
Not only can goji berries protect against ARMD, but they can also reverse diabetic retinopathy, the primary cause of vision loss in diabetic patients. Diabetic retinopathy is a condition whereby high blood sugar levels damage the cells at the back of the eye (within the retina). Untreated diabetic retinopathy can lead to blindness, so it is important to do what one can to prevent the condition.
One early marker of diabetic retinopathy is retinal pigment epithelial cell apoptosis. The epithelial cells, which form the outer layer of the retina and are vulnerable to attack from disease, maintain physiological and structural balance of the retina. When these cells die, this can significantly impair the function of retinal photoreceptors.
Taurine is reportedly beneficial for diabetic retinopathy, and it is abundant in goji berries. In a research study by Song, Roufogalis and Huang (2012), the effect of both pure taurine and goji berry extract was tested on retinal cells which had been exposed to high levels of glucose.
It was found that both pure taurine and goji berry extract led to enhanced viability of the retinal cells (i.e. they worked more effectively), and apoptosis (cell death) as a result of glucose treatment was significantly reduced.
These two studies show that goji berries may be an excellent dietary addition to anybody who is interested in looking after their vision, as they can prevent the degeneration of cells in a number of important areas within the eye.
Improves wellbeing and cognitive performance
In the modern world, stress, depression and anxiety are very real problems. Around 12 million people visit their GP each year complaining of a mental health problem, and 13.3 million hours of work are being lost each year due to these difficulties (Mental Health Foundation).
Some techniques for relieving stress and other problems have become very popular over the last few years. These include Positive Psychology (Seligman, 2000), Mindfulness (Kabat Zinn, 1982) and even Cognitive Behavioural Therapy (Beck, 1960s) for particularly problematic difficulties.
People who suffer with poor mental wellbeing may benefit from these techniques, but what may also be particularly beneficial is making changes to the diet. Research by Amagaseand Nance (2008) attempted to investigate the impact of goji berry consumption on wellbeing.
16 adults were given a goji berry juice drink to consume (120 ml) for 14 days, and 18 adults were given a placebo drink. After just 2 weeks, there were significant positive differences found in measures of happiness, contentment, feelings of health, calmness, quality of sleep, ease of awakenings and energy levels.
Not only does this study assess mental wellbeing, but it also investigates the impact of goji berries on cognitive performance. Much like the wellbeing results, the researchers found significant positive differences in measures of the ability to focus and mental acuity, suggesting that goji berries may help to increase mental sharpness.
A meta-analysis by Hsu, Nance and Amagase (2012) of four randomized controlled trials found similar results. Specifically, positive differences were found between the experimental and placebo participant groups on measures of weakness, stress, mental acuity, ease of awakening, shortness of breath, focus on activity, sleep quality, daydreaming, and overall feelings of health.
Reinforces Immune System
The immune system is responsible for defending the body from disease and infection. Human beings are constantly being exposed to pathogens (micro-organisms which can cause disease) but we rarely become ill because the immune system is extremely effective at hunting down these pathogens and destroying them before they can do serious damage.
Sometimes the immune system fails to eliminate bacteria, and when this happens disease and infection can occur. This is more likely to happen if the immune system has been weakened, which can occur as a result of stress, a poor diet, excessive alcohol consumption, lack of sleep, and excessive use of antibiotics, among other factors.
Thankfully, it is possible to strengthen the immune system. One way to do this is to adjust the diet. Eating foods high in nutrients (such as fruit and vegetables), and low in saturated fats, sugar and salt is an excellent way to improve immune function, but certain foods can lead to an even greater improvement. One of these foods is goji berries.
Elderly people are known to have a diminished immune system as a natural side-effect of ageing. Vidal et al (2012), therefore, assessed the impact of a milk-based drink supplemented with goji berries on the immune system of 150 healthy elderly participants.
The participants were given an influenza vaccine (which contains live influenza bacteria) and for 3 months consumed either the goji berry supplement or a placebo. The researchers found that the participants who consumed the goji berry supplement had a much higher level of influenza-specific antibodies (immunoglobulin G levels) and a higher seroconversion rate (this refers to the amount of detectable antibodies compared to an infectious agent).
This suggests that goji berries can help to increase the level of antibodies in the blood, and it can increase their effectiveness when fighting off antigens (infectious agents).
This study has also been supported by animal models. For instance, Ren et al (2012) discovered that goji berry supplements can reduce symptoms of influenza in mice, by decreasing inflammation and increasing the function of T-cells (cells which form part of the immune response).
Furthermore, Du et al (2014) showed that mice infected with influenza which were then fed goji berries following an influenza vaccine, showed higher levels of immune markers and reduced influenza symptoms when compared to mice that were only give the vaccine.
The mechanism by which this occurs is thought to be that goji berries improve activity of antigen-presenting dendritic cells, the role of which is to capture antigens and bring them to killer T-Cells for destruction.
Some Things to Be Aware Of
Although there are a very substantial number of health benefits associated with goji berries, it would be remiss to ignore the fact that some people may find that excessive consumption of goji berries can have some adverse health effects.
Firstly, although Vitamin A is vital to the body, too much (over 1.5 mg per day according to the NHS) can affect the bones and make them more likely to fracture. This is even more likely for those who already have brittle bones, such as sufferers of osteoporosis, or elderly people. As 100g goji berries contains just fewer than 3 mg of Vitamin A, it would not be pertinent to consume that amount more than twice a week.
Secondly, two cases of a severe allergic reaction (including anaphylaxis) to goji berries has been found in individuals who also have an allergy to tomatoes (Ballarin et al, 2011), and allergies may also occur in people who are sensitive to nuts, peach and Artemisia plants (Braun and Cohen, 2015).
Goji berries are a great food to add to your diet and bring with them some very useful health benefits. Do you like eating them?