How what you eat can help unlock the body's ability to fight disease
In his new book, Dr William Li explores how certain food stuffs can influence our health. Lisa Salmon finds out more
Most of us know getting that all-important five-a-day and avoiding junk food is good for our health. But when it comes to exactly how specific foods can support and boost our health, things can seem a lot more confusing.
This is something Harvard-trained medical doctor and researcher Dr William Li, a world-renowned expert on cancer prevention, has been looking at closely and explores in his new book - Eat To Beat Disease - which reveals the health benefits associated with more than 200 foods.
In the book, Dr Li sets out to explain how the body's defence systems, which protect health and resist disease, respond to these particular foods, shedding light on exactly why they've earned their status as being good for us.
"Health is more than the absence of disease, it's the result of our defences that are hardwired in our body, defences that protect us against cardiovascular disease, diabetes, obesity, dementia, autoimmune disease, and even cancer," says Dr Li.
"There is no 'silver bullet' for any one disease or for overall health and longevity. But my research shows we have something even better. There is a way to boost our own defence systems so the body will heal itself.
"If your goal is to extend the number of healthy years you have ahead, your food choices can tip the odds in your favour.
"Taking deliberate preventive measures using our diet is just plain common sense. What's important to know is that we can now shift our attention towards what to add to our diet, not just what to eliminate."
There are five defence systems which Li says are the key pillars of health and are influenced by diet. These are: angiogenesis (the process by which blood vessels taking oxygen and nutrients to our cells are formed); regeneration (more than 750,000 stem cells repair, regenerate and maintain our bodies); microbiome (almost 40 trillion bacteria inhabit our bodies, producing health-supporting metabolites from food and also controlling the immune system and influencing angiogenesis); DNA protection (DNA's genetic blueprint is designed to protect itself against damage), and, immunity.
Of course, these processes are influenced by more than diet alone, but food, as Dr Li explains, can play a significant role in supporting, promoting or dampening their function.
Curious to know what the 'magic foods' are? Here are seven disease-beating ingredients from Dr Li's book...
Public confusion over soya rests on a mistaken belief that an oestrogen-like compound found in soya can cause breast cancer, says Dr Li, who explains that research shows plant oestrogens in soya may actually be protective against breast cancer. Large epidemiological studies of women with breast cancer show that eating a diet high in soya foods is associated with decreased risk of breast cancer recurrence. "A reason to love and not fear soy foods," he says.
Tomatoes contain a bioactive molecule called lycopene, Dr Li explains, that can starve cancer by helping to cut off the blood supply that feeds cancer cells. A large US study last year showed that consuming 470-700ml of cooked tomatoes per week was associated with a 30% reduced risk of prostate cancer.
3. Dark chocolate
Dark chocolate, rich with cacao, doesn't have to be such a guilty pleasure, as Dr Li says research shows cacao contains polyphenols that can raise levels of regenerative stem cells in the bloodstream, improving circulation and helping our bodies repair and regenerate organs as we age.
Green tea has been recognised for its health benefits for years, but Dr Li says black tea joins it as a health-booster. Both green and black teas can activate all five of the body's health defence systems, including improving circulation, regeneration, healthy gut bacteria, DNA protection, and immunity.
The benefits of coffee go beyond a caffeinated jolt. Research has shown that drinking coffee can help slow cellular ageing by increasing the length of telomeres, the cap protecting the ends of chromosomes, which contain our DNA. Multinational studies also show drinking two or more cups of coffee per day is associated with a decreased risk for all-cause mortality.
Mango contains fruit sugars, but with this also comes fibre, vitamins, minerals, and health-promoting bioactives that can boost health defences. Dr Li identifies mangoes as a 'grand slammer' because the fruit activates all five health defence systems, from angiogenesis to regeneration, microbiome, DNA protection and immunity.
Packed with nutrients and healthy fats, tree nuts are also a health-activating food. Studies show two servings of tree nuts, like walnuts, each week is associated with a reduced risk of colon cancer, as well as slowed cellular ageing, and a healthy microbiome. In addition, scientists have discovered that walnuts contain a natural substance that kills cancer stem cells.
Eat to Beat Disease: The Body's Five Defence Systems and the Foods that Could Save Your Life by Dr William Li, published by Vermilion on March 21, is priced £16.99