In this, my third update on the 5th International Plant-Based Nutrition Healthcare Conference (PBNHC), held in Anaheim, California in September 2017, I’m going to summarise 3 presentations that focused on cancer.
Dr William Li’s presentation was provocatively titled ‘Can You Starve Cancer?’; oncologist Delia Garcia’s presentation, ‘Breast Cancer Prevention and Plant-Based Nutrition’ zeroed in on most women’s biggest health-related fear; and Dr Bharat Aggarwal spoke about ‘Inflammation, Diet and Disease: Food Solutions’, with a particular emphasis on dietary prevention and even treatment of cancer.
(Missed the first two updates? Read Part 1 – The 3 secrets of transforming your life and Part 2 – Beating Diabetes.)
Can You Starve Cancer?
Dr Li’s primary research interest is angiogenesis, the process of forming new blood vessels from existing ones. I covered his 2015 PBNHC presentation, in which he discussed the role played by angiogenesis in a broad range of health conditions, from endometriosis to rosacea, in a previous post. This year’s lecture was all about angiogenesis and the big ‘C’.
As Dr Li explained, when cancerous tumours first begin, the damaged cells divide so rapidly and in such a disorganised fashion, that they quickly outgrow their blood supply. Without developing a reliable blood supply, a tumour can reach a maximum size of 1-2 mm, which is clinically insignificant.
However, once a tumour manages to secure a blood supply, it can increase in size by a mind-boggling 16000 times in just a couple of weeks. How does the tumour supply itself with blood? By stimulating angiogenesis. Tumours release pro-angiogenic chemicals that cause neighbouring blood vessels to sprout extensions that grow into the tumour, feeding it with the oxygen and nutrients that it needs to continue growing.
And that’s where diet comes in.
Most people think that cancer is primarily a genetic disease (in the sense of being caused by inheriting ‘faulty’ genes), but in fact only 5-10% of cancers are genetic, while the remaining 90-95% are due to environmental factors, with an estimated 30-35% of all cancers linked to diet.
There are multiple compounds found in plants that inhibit abnormal angiogenesis, thus preventing or slowing the growth of cancers to the point at which they become clinically apparent, and potentially life-threatening. And they don’t just inhibit angiogenesis in cancer cells growing in a petrie dish – they do it in real, live people eating actual food.
For example, genistein, an isoflavone compound found in soybeans, has long been known to have antiangiogenic properties. In fact, in laboratory assays, soy isoflavones compare favourably to antiangiogenic drug, such as Avastin.
Does that benefit translate to actually eating soy and other isoflavone-rich foods? A recently published study, Dietary isoflavone intake and all-cause mortality in breast cancer survivors: The Breast Cancer Family Registry found that among North American women with breast cancer, from a range of ethnic backgrounds, those who consumed the most dietary isoflavones (not isoflavone supplements) were less likely to die of any cause.
Other powerful angiogenesis-inhibiting substances occur in tomatoes, and cooking the tomatoes enhances the bioavailability of these compounds. Dr Li referred to a study showing a 40-50% lower risk of dying from prostate cancer in men who ate 2-3 serves of cooked tomatoes per week. The reduced death rate was due to decreased tumour vessel area and vessel abnormalities in the tomato-eating men – that is, their prostate cancers were smaller and less vascular.
Dr Li also extolled the value of tea as a form of food-as-medicine, with black, sencha, Earl Grey and green teas all demonstrating powerful angiogenesis-inhibiting activity. Interestingly, agitating the tea bag results in 15% more anti-angiogenic catechins in the brew, so don’t forget to dunk!
An emerging area of research in Dr Li’s field is the effect of the gut microbiome on angiogenesis. One fascinating finding is that eating one or more apples per day reduces risk of colorectal cancer by 20%, and this risk reduction is partly mediated by the production of hydroxybutyrate by the gut microbiome from pectin, a form of carbohydrate that apples are rich in.
Inflammation, Diet and Disease: Food Solutions
The delightful Dr Bharat Aggarwal picked up the food-as-medicine baton from Dr Li, taking us deep into his decades of research into the role of inflammation in chronic diseases, including cancer, and the effect of substances found in common foods – especially spices. As he pointed out, dysregulated chronic inflammation caused by lifestyle factors mediates all chronic diseases including cancer.
Dr Aggarwal discovered the inflammatory cytokine (cell signaling protein) tumour necrosis factor (TNF) early in his research career, finding that it promoted the progression of cancer in human patients.
While a wide range of drugs that inhibit TNF have been developed (monoclonal antibodies such as infliximab [Remicade] and adalimumab [Humira], and circulating receptor fusion proteins such as etanercept (Enbrel)], the so-called active ingredient of the spice turmeric, curcumin, is a potent TNF inhibitor whose anti-inflammatory activity is comparable to steroid drugs… but without the laundry list of side-effects.
The transcription factor nuclear factor kappa B (NFκB) regulates 500 genes involved in inflammation. Excessive activation of NFκB is seen in most chronic diseases, including cancer, and inhibiting NFκB can prevent or delay the onset of cancer.
Unfortunately, both chemotherapy and radiation activate NFκB, which means that they are feeding the inflammatory process that underpins the growth and spread of cancer.
On the other hand, a wide variety of plant possess NFκB-inhibiting properties, including traditional Ayurvedic herbs such as amla, guggul, frankincense, ashwagandha, pepper and neem; as well as resveratrol from red grapes and peanut skins, indole-3-carbinol from cruciferous vegetables, and tocotrienols, members of the vitamin E family.
So many of the foods you can choose to eat each day are powerful medicines.
Breast Cancer Prevention and Plant-Based Nutrition
Dr Delia Garcia takes food-as-medicine so seriously, she actually quit her oncology practice and now works as a health coach for women battling breast cancer.
With decades of oncology practice under her belt, she had some worrying insights into the cancer business. For starters, she pointed out that in most clinical trials of drugs, including cancer drugs, there is now no longer a control arm in which the new drug is tested against an inert placebo. Instead, the effectiveness of the new drug is compared to that of a drug that’s already in use, which was most likely tested against another drug that was already in use, and so on and so forth. And a drug can be approved if its sponsor produces just two studies showing that it is not less effective than an existing treatment, no matter how many studies show the contrary.
Most of the ‘blockbuster’ cancer drugs fail to show any real benefit in terms of what matters most to cancer patients and their families – living longer, and in a state in which life is worth living.
Secondly, Dr Garcia warned that women with early-stage breast cancers are being overtreated. Back in the 1980s, women with small, slow-growing breast cancers that were estrogen receptor positive and lymph node negative were given minimal treatment – just a lumpectomy, in most cases – but the cure rate was 95%.
Now, women with these low-risk tumours are usually treated systemically with chemotherapy and radiation, and this overly aggressive treatment puts them at risk of serious complications of treatment, including heart disease from radiation therapy, for no benefit.
Losing a breast is psychologically devastating to many women, but Dr Garcia pointed out that breast cancer survival rates in women who have a lumpectomy are as good as mastectomy survival rates in most cases.
Echoing Dr Li’s point that our genes play a relatively minor in cancer, Dr Garcia explained that only 5% of breast cancers are attributable to the well-publicised BRCA genes, and less than 1% of the general population carries these genes (although about 2% of Ashkenazi Jews are carriers).
Family history does play a role in breast cancer though, with a woman’s risk doubling if her mother, sister or daughter has had it, tripling if she has 2 relatives who developed breast cancer, and quadrupling if she has 3 or more relatives with it.
But there are many things women can do to reduce their risk, including:
- Maintaining a healthy weight – obese women have twice the risk as women in the healthy BMI range, while gaining just 11 lb (5 kg) leads to an 11% increase in breast cancer risk;
- Being physically active – sedentary women have a 25% higher risk of developing breast cancer, while a meta-analysis of 70 studies found that exercising regularly reduces the risk of dying of breast cancer by 40%;
- Avoiding alcohol – even 1 drink per day increases breast cancer risk, while just 2-3 drinks per day raises risk by 20%;
- Avoiding HRT; and
- Avoiding statin drugs – women taking statins for 10 or more years have double the risk of invasive breast cancer.
What about women who have already had breast cancer? They can reduce their risk of recurrence by 25% by consuming 1 cup of soy milk, or ½ cup of tofu, or 1 cup of edamame each day. They should also cut back on fat: Dr Garcia cited a trial which found that women who dropped their fat intake from 40% of daily energy to 20%, reduced their 5 year breast cancer recurrence rate by 24%, even if they had a less-favourable estrogen receptor negative tumour.
My favourite quote from Dr Garcia’s presentation was this one:
“People do not decide their futures. They decide their habits and their habits decide their futures.”
And practising just 5 habits can lower a woman’s risk of breast cancer by 30%:
- Don’t smoke
- Drink very little or no alcohol
- Maintain a healthy body weight
- Don’t use HRT
- Walk 30 minutes per day.
Talk about a massive pay-off for a modest investment!
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