After years of listening to ever-changing advice on healthy eating, it can be easy to become confused about what foods you should include in your diet in order to optimise your wellbeing.
A ground-breaking new book by U.S. doctor and scientist Dr William Li, who has immersed himself in the study of how certain foods can help us fight disease.
His lifelong work is centred on the study of the body’s five key defence systems — immunity, stem cells, gut bacteria, blood vessels and DNA protection — and research that identifies the specific compounds in certain foods that support them.
He has sifted through research to provide scientifically backed advice.
The true ‘superfoods’ — foods that work hard to enhance all five of the body’s health defence systems.
He also explains the important disease-fighting role played by your stem cells — and reveals the foods that can keep them working efficiently.
Our stem cells are the special forces in our body that gather intelligence, conduct reconnaissance and execute missions to keep organs in optimal shape. Whenever you suffer an injury or develop a disease, your stem cells swing into action: repairing, replacing and regenerating dead and worn-out cells on demand.
How stem cells work is still something of a mystery, but we do know they are factories for important chemicals needed in organs that are growing or being repaired.
They help mend and build bone and skin, nerves and hair, so to support your own defence against illness and disease, you should aim to eat at least one food that can protect and support your stem cells every day.
We know babies are born with a rich supply of stem cells that prompt growth and development, but their number — and potency — diminishes with age.
Over time, stem cell activity can also be knocked back by smoking, air pollution and alcohol. When this defence system comes under pressure, your body can get to the state where there aren’t enough stem cells to repair blood vessels, heart muscle and brain tissue.
Chronic wounds in the feet, ankles and lower legs also need stem cells to regenerate healthy tissue and close the injury, in order to avoid infection and the development of deadly gangrene.
When the muscles, tendons and nerves of your legs start dying in peripheral arterial disease (a narrowing of the blood vessels in the legs), the body will try to call in stem cells to reverse the damage.
If you are pre-diabetic or have type 2 diabetes, the high blood sugar levels can damage stem cells and lower their numbers, reducing your body’s ability to repair itself. Many of the complications of diabetes (heart attack, stroke, blindness, kidney failure, chronic wounds) are tied to dysfunctional stem cells.
In fact, many conditions that are associated with ageing (such as Parkinson’s and Alzheimer’s, as well as cardiovascular disease) can be exacerbated if your stem cell defence system is not working optimally.
So, turn the page to find the ‘superfoods’ that enhance your body’s defence mechanisms.
How to heal your body from the inside out
Whether you are healthy and want to optimise your strength and simply age gracefully, or you have a serious chronic condition, such as heart disease, Alzheimer’s, diabetes or even cancer, there’s a way to use diet to direct stem cells to help you heal from the inside out.
Studies show the stem cells in bone marrow, skin, the heart and other organs can be called into action by what and how we eat.
Selecting the right foods can help you kick your stem cells into action to help grow muscles, maintain vigour and slow the ravages of ageing.
Not only do stem cells keep you youthful, they can also regenerate tissues damaged by ageing, prompting the body to heal more quickly.
As a basic rule, it is important to know that high-fat, high-salt or high-sugar diets can stunt stem cell activity, but Mediterranean and Asian dietary patterns have been shown to help them.
Eating to support your stem cells can help your body fight chronic disease. If you’ve had a heart attack or a stroke, for instance, your stem cells can help save your heart and rebuild your brain.
If you’ve had surgery and need to heal quickly, or if you are recovering from an illness and want to bounce back to health, or if you’re just middle-aged and you want your body to stay youthful, the good news is certain foods can increase your circulating stem cells.
By supporting the body’s regenerative defence system, these foods can help influence everything from repairing damaged organs to counterbalancing the effects of eating too much fat.
Food and drinks that help to recruit stem cells include turmeric (it contains curcumin, which has pro-regenerative properties), red wine (one to two glasses daily) and green tea (four cups a day increased stem cells by 43 per cent in two weeks, according to one study).
Dark chocolate, black tea and beer can mobilise stem cells, too, and help our bodies regenerate.
One study in California gave patients with known heart disease two daily cups of hot chocolate, made with 70 per cent dark chocolate. After 30 days, the number of stem cells in their blood had doubled.
No known medicine has the same effect. The fruit, vegetables, whole grains, legumes, nuts, olive oil and fish eaten by those who follow a Mediterranean diet also help to stimulate stem cells.
Each food contains its own trove of defence-activating active compounds (‘bioactives’).
Cancer-fighting purple potato
Not all stem cells are beneficial. For instance, cancer can create stem cells that help the disease to return after treatment.
But some food compounds (such as one found in purple sweet potatoes) are so sophisticated they can target and reduce these rogue stem cells without affecting the action and activity of helpful ones.
The anti-cancer effects are preserved whether the purple potato is boiled, baked or cooked as potato crisps. Green tea can kill rogue cancer stem cells (which form new cancers), too. If you have cancer, or have ever had it, your number-one focus should be to kill those stem cells.
There’s no medicine that can do this yet, but there are a growing number of foods, and their bioactives, that are being studied for their suppressive effects on cancer stem cells. Finding ways to kill cancer stem cells has been one of the holy grails in cancer research.
While biotechnology companies are busy looking into this, scientists have already discovered dietary factors that have the ability to kill them, at least in some forms of cancer.
Other foods containing bioactives shown to suppress cancer stem cells include soya, celery, oregano, thyme, capers, apples and peppers.
Scientists in Korea discovered that resveratrol — the bioactive that is found in red wine, grapes, peanuts, pistachios, dark chocolate and cranberries — also interferes with the growth of breast cancer stem cells.
Eat to beat illness
Some foods work hard to enhance not just one or two, but all five of the body’s health defence systems. When it comes to beating disease, these are true ‘superfoods’ so, if you do nothing else, add them to your weekly shopping list and aim regularly to incorporate them into your diet.
Olive Oil
A good virgin olive oil is packed with compounds that have been shown to have anti-angiogenic (i.e. inhibiting the growth of rogue blood vessels), anti-inflammatory and unique anti-cancer properties.
Extra-virgin olive oil is a key part of the Mediterranean diet and the active compounds (‘bioactives’) that it contains can enhance your immune system and reduce the body’s reaction to allergens. Studies show bioactives known as secoiridoids could reduce the growth of cells that can fuel breast cancer.
Buy extra-virgin cold-pressed oil made from one type of olive, rather than a blend.
In our studies, the best olives are: Koroneiki (from Greece), Moraiolo (Italy) and Picual (Spain).
Stone fruits
Peaches, plums, nectarines, apricots, cherries, lychees and mangoes contain a host of anti-angiogenic (and regenerative, as well as DNA protective) bioactives that have been shown to help fight cancer.
Some are more potent than others: plums have three times the amount of cancer-fighting polyphenols as peaches.
Meanwhile, apricots contain a carotenoid called lutein that prevents the formation of the brain-damaging compounds found in Alzheimer’s disease. And while mangoes are a great source of bioactive carotenoids (which give the flesh its colour), they also contain mangiferin, which has anti-tumour, anti-diabetic and cell-regenerating properties.
Cherries contain bioactives much loved by your gut bacteria, shown to reduce tumour development.
Bamboo shoots
Popular within Eastern cuisine, you can buy tinned bamboo shoots in supermarkets in the UK.
The shoots are extremely high in fibre and bioactives that have been shown to aid weight loss (in mice) and to increase bacterial diversity in the gut.
Coffee
Studies show that caffeine isn’t so healthy — it can affect the heart and hasten the ageing process — but coffee contains many more bioactives than caffeine, which work together to offer a protective effect.
A large UK study recently showed that one to two cups of coffee per day can give a 21 per cent reduced risk of death from heart attack, and two or more cups can give a 31 per cent reduced risk of death.
It could help fight cancers, too. Coffee beans have polyphenols that can unleash tumour suppressors in our DNA, thus thwarting the ability of cancers to grow.
Squid Ink
This black liquid produced by cuttlefish contains compounds shown to not only inhibit ‘bad’ angiogenesis, but also protect stem cells. Laboratory research has shown squid ink can also have antioxidant and immune-enhancing effects. It can even protect beneficial gut bacteria against the nasty side-effects of chemotherapy treatment.
Aubergine
This purple-skinned vegetable is a rich source of chlorogenic acid, which activates your stem cells. It also has angiogenic properties (it helps ‘good’ blood vessel activity) and bioactives that boost your beneficial gut bacteria —which, in turn, protects your DNA and immunity.
Kiwi
This fluffy-skinned green fruit has high levels of vitamin C, chlorogenic acid and quinic acid, which each has anti-oxidant effects that help to neutralise free radicals that can otherwise damage cells.
Researchers in Scotland found that eating one or two kiwi fruits a day could reduce DNA damage by around 60 per cent, increasing the repair rate of any damaged DNA and helping it get back into shape.
The flesh also has a prebiotic effect that helps feed beneficial gut bacteria and lower inflammation throughout the body.
Carrot
Carrots are among a select group of foods rich in the compound chlorogenic acid —which, Japanese scientists found, may block the genes supporting cells that fuel lung cancer. It works to increase the activity of genes that kill cancer cells, too.
Carrots are also a rich source of powerful bioactives called carotenoids and are ‘powerhouses’ of anti-oxidant activity.
The combination of vitamins A, B, C, D and E found in carrots makes them great for DNA, with one UK study showing five carrots a day for three weeks is enough to increase the DNA repair activity you need to fight disease.
Walnut
All nuts are a great source of omega-3 fatty acids, which have an impressive cancer-fighting effect, and are rich in fibre, good for your gut bacteria.
Studies show eating nuts can also slow the ageing process.
Of all the nuts, walnuts are best, as they are nutrient- dense and contain bioactives shown to, among other things, reduce the risk of developing colon cancer and improve survival in patients who already have colon cancer. Studies show walnuts improve anti-inflammatory bacteria in the gut, too, and decrease harmful gut bacteria.
Walnuts also contain ellagic acid, a potent bioactive that supports your defence systems and has anti-angiogenic effects, which can ‘starve’ tumours and stop their growth. It assists immune cells, too, by improving their ability to detect and destroy cancer cells.
Seeds
Flax seeds, sunflower seeds, sesame seeds, pumpkin seeds, and chia seeds contain bioactives called lignans that are proven to stimulate the growth of ‘good’ blood vessels in the heart after an attack. They are also high in fibre, which can lower ‘bad’ cholesterol levels and feed beneficial gut bacteria.
Blueberries
The intense colour and tartness of these popular berries indicate the presence of potent bioactives, and large studies have linked berry consumption with lower cancer risk. They also have remarkable immune-influencing powers and can calm excessive inflammation.
Dark Chocolate
Dark chocolate contains compounds that can lower your risk of heart disease and diabetes, protect your DNA and improve gut bacteria.
Studies show that drinking hot chocolate made with high concentrations of cocoa solids can increase your stem cells and improve blood flow as effectively as statins (which keep arteries clear by lowering cholesterol).
That’s because cocoa powder contains flavanols that have been linked to a lower incidence of death from cardiovascular disease. Active components in dark chocolate can even switch cells in your immune system from a pro-inflammatory to an anti-inflammatory state.
Specific bioactives have potent anti-angiogenic effects that can ‘starve’ tumours and boost ‘good’ gut bacteria, while controlling ‘bad’ bacteria. One study in the Netherlands found eating dark chocolate for only two weeks is enough to influence your gut bacteria and reduce stress hormone levels.
Kale
This leafy green vegetable contains at least six anti-angiogenic ingredients — the best form is cavolo nero. As a member of the brassica family (which includes broccoli, cauliflower and rocket), kale has proven health benefits. It has been shown to helpfully adjust the balance of gut bacteria, decreasing harmful bacteria that produce hydrogen sulphide, which would damage the gut lining.
This helps to protect against the development of colitis and gut inflammation.
Tea
Ordinary tea leaves contain more than 2,000 active ingredients. Studies have shown that tea extracts can halt the progress of the rogue blood vessels that feed cancers and arterial plaque (fatty build-ups) as effectively as drugs.
Standard black tea has been shown to help mobilise stem cells and it can also reduce blood pressure, by improving your blood vessels’ ability to dilate.
Different tea blends have different levels of health benefits.
Chinese jasmine tea is more potent than Japanese sencha tea, and Earl Grey is even more potent than jasmine. But we believe the best blend for blood vessel growth is sipping a mix of sencha with jasmine.
In addition to their antioxidant, anti-inflammatory and anti-angiogenic properties, the polyphenols (plant micronutrients) in tea are loved by your gut bacteria.
Black, oolong and green tea have been shown to increase your levels of ‘good’ bacteria, decrease the ‘bad’, and help your microbiome produce beneficial short-chain fatty acids.
Green tea contains 16 times the level of the important compound epigallocatechin gallate (EGCG) compared with black tea. EGCG has been shown to reduce harmful angiogenesis and cancer growth, lower blood pressure, improve blood lipids and maintain immune cells, plus it has antioxidant and anti-inflammatory properties.
Scientists have also found drinking green tea can stimulate regeneration of the brain, muscle, bone and nerves to promote healing.
When researchers examined the effects of green tea on the stem cells of smokers, they found drinking four cups a day increased the number of circulating stem cells by 43 per cent over two weeks.
Green tea also triggers the production of a natural antioxidant enzyme that protects DNA by neutralising free radicals.
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