If you love garlic but haven’t yet tried the aged, black garlic version, you’re in for a treat. As well as offering health benefits, black garlic has a lovely, soft, savoury-sweet flavour with undertones of molasses and balsamic. As a bonus, black garlic does not have a strong odour and is more socially acceptable for long-term users. Black garlic can be added to any savoury dish in place of raw white garlic, but add it towards the end of cooking for maximum effect. Once any garlic is heated for more than 3 minutes, its medicinal benefits are rapidly reduced and, after 10 minutes of heating, the ability of garlic to reduce platelet clotting is completely suppressed.
Black garlic benefits
Black garlic is produced by naturally fermenting fresh garlic bulbs under controlled conditions of high temperature (70 degrees) and high humidity (90%) for at least 21 days. This converts unstable, volatile, smelly sulphurous compounds into stable, odourless substances. Five new amino acids are also generated, along with dark pigments, called melanoidins, which turn the garlic cloves black.
The most exciting change is that the polyphenol content increases by a factor of five as sulfur-based substances, such as allicin, which are responsible for the pungent smell of cut fresh garlic, are converted into other non-smelly substances including flavonoid polyphenols.
Aged black garlic has significantly greater antioxidant activity than non-fermented garlic, offering at least four times more antioxidant activity per gram (and the antioxidant capacity of raw garlic is already high). It therefore has the potential to offer greater health benefits.
The origins of black garlic lie in Korean medicine, centuries ago, and spread to China and Thailand where it was revered as an anti-ageing supplement used to promote longevity. Black garlic is now available in mainstream supermarkets and features on the menu of high-end restaurants.
Black garlic and immunity
Black garlic extracts increase the activity of circulating white blood cells in samples analysed in the laboratory. By increasing the proliferation and activity of these immune cells such as macrophages and natural killer cells, black garlic extracts may improve immune targeting of abnormal body cells.
Cell studies also suggest that aged black garlic extracts can inhibit the growth of stomach cancer, colon cancer and leukaemia cells by triggering their natural self-destruct mechanism (apoptosis). These findings must be treated with caution but may suggest a useful preventative role for black garlic if confirmed in human trials.
Anecdotal evidence suggests that black garlic extracts may reduce symptoms of allergies such as runny nose (rhinitis) and watering eyes. This effect may relate to reduce activity of the B lymphocytes which produce the IgE antibodies linked with allergic reactions.
Black garlic and cholesterol
Black garlic improves cholesterol balance by increasing liver production of the ‘good’ HDL-cholesterol which protects against hardening and furring up of the arteries.
A 12-week study compared the effects of black garlic extracts (6g per day divided into two doses taken before the morning and evening meal) against placebo in 60 volunteers with a mildly raised cholesterol. No significant differences were seen in LDL-cholesterol, total cholesterol or triglycerides but ‘good’ HDL-cholesterol levels increased by an average of 7.45% to significantly lower the projected ten-year risk of heart attack or stroke.
There is also increasing evidence that black garlic helps to reduce the accumulation of fat in liver cells, but this has not yet been confirmed in humans.
Black garlic and diabetes
Raised glucose levels generate free radicals that are associated with a number of diabetes complications. Black garlic helps to quench these through its powerful antioxidant action and may also improve glucose control. If you have diabetes, always monitor glucose levels closely when making any dietary or lifestyle changes, including starting a new supplement.
Black garlic and blood pressure
Black garlic can lower blood pressure in a number of ways, by dilating blood vessels, reducing blood stickiness, by increasing the elasticity of artery walls, and by blocking a hormone called angiotensin II in the same way as some antihypertensive drugs.
A study involving 88 people with uncontrolled high blood pressure found that adding 1.2g aged garlic supplements to their diet every day reduced their blood pressure by 5/1.9 mmHg compared with those taking an inactive placebo. Some responded better than others, and in ‘responders’ blood pressure lowered by 11.5/6.3 mmHg on average.
The only way to know if you are a garlic responder is to take a standardised supplement for up to three months to see if it brings down your current average readings.
Black garlic and blood clotting
Garlic reduces the stickiness of blood to reduce platelet clumping and unwanted blood clots. Studies suggest that eating the equivalent of one clove of fresh garlic per day can reduce blood levels of a substance called thromboxane which is involved in the stimulation of thrombosis.
Black garlic and weight loss
Black garlic extracts have been found to reduce the accumulation of fat in cultured human fat cells by 15% compared to cultures to which no black garlic was added. Follow up studies suggest that black garlic extracts significantly reduce the formation of white adipose tissue when following a high fat or a high sugar diet. Black garlic also reduce fat accumulation in liver cells, which is a feature of obesity, metabolic syndrome and type 2 diabetes.
Black garlic dose
Black garlic may have additional beneficial biological effects similar to those of raw garlic, but research is in its early days and effects on blood clotting, blood pressure and arterial elasticity have not yet been confirmed. Even so, the growing evidence base may explain why many Eastern cultures revere black garlic as an anti-ageing supplement used, like ginseng and red reishi mushroom, to increase longevity.
A typical dose for black garlic is 200mg concentrated extract, equivalent to 2g whole garlic.
I now take black garlic supplements rather than garlic tablets and have started experimenting with its use in the kitchen. I guess I smell sweeter as a result!
How to add black garlic to your diet
You can simply spread a clove of black garlic onto dark rye bread, or use black garlic in any savoury dish wherever you would normally use raw garlic, such as when making a pasta sauce. Add it towards the end of cooking for maximum effect.
Once garlic is oven-heated (at 200 degrees C) or boiled for more than 3 minutes, its medicinal benefits rapidly reduce so that after more than 10 minutes heating, its ability to reduce platelet clotting is completely suppressed.
Image credits: Isle of Wight Garlic Farm