A patient recently asked: “I have been told to give up all sugar and all grains, but surely that is ridiculous. I’ve looked into it, and the case for sugar is not proven,and surely wholemeal bread and brown rice can’t be bad?”
The truth is, they are dangerous foods for you if you have cancer, and there is a clear biochemical and physiological foundation for the advice.
Just as the human body contains organs, each with their specific functions, so the cell contains much smaller, individual, organelles with their own specific functions, such as mitochondria.
Each of your cells has thousands of these mitochondria, and they are unique in that they contain oxygen, whereas the rest of the cell and all the other organelles are anaerobic, or oxygen-free.
It is the mitochondria that contain the necessary materials and mechanisms for releasing the energy locked up in the food you eat, and they are where you ‘burn up’ the fats, proteins and most of the carbohydrates you eat to release the energy they contain, making it available for the cell to use. All of the energy you obtain from proteins and fats is released here and also, arguably, around 90 to 95 per cent of the energy contained in carbs.
Cancer’s sweet tooth
In 1924,the eminent German physiologist Otto Warburg demonstrated that the cause of cancer was a lack of oxygen and, thus, failure of mitochondrial function,1 a claim for which he eventually won a Nobel Prize in 1931.
As he stated, “The cause of cancer is no longer a mystery; we know it occurs whenever any cell is denied 60 per cent of its oxygen requirements . . . Cancer, above all other diseases, has countless secondary causes.But, even for cancer, there is only one prime cause: the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar.”2
This increased appetite for glucose could be because most malignant cells have deficient or defective mitochondria, the powerhouses of cells that create energy.3
If cancer cells have lost mitochondrial function, it follows that they cannot obtain energy from fats or proteins and so become desperate for carbohydrate, in the form of glucose, as an energy source. Cancer cells have been shown to have a three- to fivefold increase in glucose uptake compared with healthy cells.4 In fact, so desperate are cancer cells for glucose that they have many more receptor sites (entry portals) for glucose than do normal healthy cells; there are various estimates as to the number, ranging upwards ofsix times as many.5
This characteristic of cancer cells to feed on glucose is the basis of tumour-imaging using labelled glucose analogues [such as fluorodeoxyglucose positron emission tomography (FDG–PET) scans], and has become an important diagnostic tool for cancer detection and management.6 And as insulin is needed to increase cellular uptake of glucose, it’s not surprising to find that cancer cells have many more receptor sites for insulin than do healthy cells.5
Cancer cells have devised another clever tool to take in glucose and feed their insatiable appetite for it: special channels called ‘epidermal growth factor receptors’ (EGFR). These stabilize a protein that sends a constant supply of glucose into cancer cells.7
To improve their chances of getting the lion’s share of glucose from your bloodstream, cancer cells actually make their own insulin, the hormone essential for, and which encourages, cellular uptake of glucose.
Not only does glucose feed cancer, but it has been argued that most cancer cells would die if starved of glucose.
Research carried out by Thomas Seyfried, professor of biology at Boston College and author of Cancer as a Metabolic Disease: On the Origin,Management and Prevention of Cancer, indicates that genomic instability and essentially all hallmarks of cancer, including the Warburg effect—whereby cancer cells produce energy by ‘aerobic glycolysis’,converting glucose into lactic acid in the presence of oxygen—can again be linked to the fact that cancer cells have impaired mitochondrial function and,therefore, energy metabolism.8
In fact, malignant cells are able to reprogramme their glucose metabolism—and, thus, their energy production—by limiting their energy metabolism largely to glycolysis in cell cytoplasm.But this process is very inefficient for generating energy. Mitochondria can create around 20 times more adenosine triphosphate (ATP, the energy ‘currency’ of cells) than the process of glycolysis does.
To compensate for this lower efficiency, cancer cells have developed the ability to upregulate glucose transporters, notably GLUT1, which significantly increase the movement of glucose into cells.6 Rapidly growing tumour cells typically have glycolytic rates up to 200 times higher than those found in their normal tissues of origin.9
Like any cells, malignant cells require signalling hormones that tell them to grow and survive, including insulin-like growth factor (IGF) receptors, which bind IGF and also insulin, secreted in the bloodstream in response to carbohydrate consumption. Insulin then activates several pathways that can increase cancer growth and survival.3
Given their faulty mitochondria, cancer cells must also depend on glucose to fix any damage from free radicals. Much like normal cells, cancer cells are under constant attack by free radicals, unstable molecules formed in the body by natural physiological processes and also by the environment. As their mitochondria aren’t working properly, they must rely even more
on the uptake of glucose to counteract free radical damage.
All of which means, quite simply, that glucose feeds cancer. Keep that firmly in mind when choosing your foods.
The ketogenic diet
As cancer cells rely on glucose to fuel their metabolism, researchers are investigating ketogenic diets as a cancer therapy.10 These diets have been effective for seizure control in epileptic children for almost a century,11 but since the 1960s, they’ve been widely recognized as one of the most common methods for treating obesity and its related disorders.12
The cornerstone of a ketogenic diet for cancer patients involves the severe restriction of carbs (to 2–4 per cent of total calorie intake) to minimize their effect on blood glucose. The carbs are replaced by large amounts of fat (75–80 per cent of total calorie intake) in the form of coconut oils, avocados and oily fish, for example, and adequate intakes of vegetable and animal protein (12–20 per cent of total calorie intake).13 However, patients need to monitor their protein intake as excessive protein consumption can result in raised blood glucose levels through a process called ‘gluconeogenesis’ (where glucose is made from non-carbohydrates).14
A ketogenic diet causes the body to enter a state of ketosis, where ketone bodies are produced by the liver as a result of fat breakdown when blood glucose is low.Unlike normal cells, data show that cancer cells cannot effectively generate energy from ketone bodies but instead must rely heavily on glucose.14 And as cancer cells rely on glucose for energy, a ketogenic diet could fight cancer simply by limiting the glucose available to malignant cells.15
It has been theorized that, because tumour cells don’t seem to have themetabolic flexibility to use ketones for energy, a ketogenic diet could destabilize tumour tissue DNA, reduce tumour growth over time and so enhance survival rates for cancer patients.16 It also makes sense that limiting glucose will inhibit the cancer’s capacity to repair its damaged cells.17 This may be one of the reasons why restricting glucose through a ketogenic diet also appears to enhance the effects of radio- and chemotherapy.18
A preliminary study of 10 advanced-cancer patients carried out in 2012 tested the hypothesis that a low-carb ketogenic diet might inhibit cancer growth in patients by reducing the secretion and circulating levels of insulin. After about a month on the diet, the extent of ketosis was found to be linked to cancer stabilization or partial remission.19
Minimizing the pathways leading to cancer growth or, indeed, activating those that limit it, such as the AMPK (adenosine monophosphate-activated protein kinase) pathway—activated by decreases in ATP to make more ATP (which transports chemical energy within cells)—is another potential mechanism by which a ketogenic diet can be effective.
But although it seems a reasonable possibility that a ketogenic diet can help to reduce the progression of some types of cancer, the evidence at present is preliminary. Most trials of a ketogenic diet have been animal studies and case reports, with only a few larger, randomized controlled trials currently underway.
Following the ketogenic diet
A low-carb diet is just one of the many nutritional and lifestyle interventions that can be used in the management of cancer, but it’s certainly a very promising one.
Nevertheless, the ketogenic diet has its drawbacks: it requires total compliance and careful monitoring by a trained professional nutritionist familiar with the required metabolic tests, contraindicated health conditions and medications.
This professional should also ensure that the diet doesn’t starve you of vital macronutrients (carbs, fats, proteins) or micronutrients (vitamins, minerals). Anticancer nutriceuticals (like curcumin,omega-3 fatty acids, green-tea polyphenols) are equally important and should be considered when evaluating your diet.20
As with any dietary intervention during cancer treatment, a multidisciplinary approach is vital, and involves investigating synergistic interactions
between different therapies that might increase treatment efficacy.21
So, if you’re a cancer patient, how should you plan your diet? First, give up all sugars, grains, beans and other high-starch foods. Sugars come in many different guises, such as dextrose, maltodextrin, agave and corn syrup, so become sugar-wise and learn to read labels. If this is too much for you, first give up all sugars, then give up refined grains and then all grains.
If you still want to eat legumes, sprout them. This will turn their starch into cellulose and other non-digestible carbs that support the growing plant structure, but won’t break down within your digestive tract, so not adding to your glucose intake.
Of course, you can’t go on a totally glucose-free diet, but by focusing on above-ground vegetables, good-quality proteins, nuts and berries, you can avoid the floods of glucose thatresult from eating sugars (of all sorts), grains and other starchy foods.
Where sugar comes from
Sugar is made up of glucose and fructose (fruit sugar) joined together to form a double molecule. In your body, fructose is converted to glucose so, essentially, when you eat sugar in any form, including fructose, you’re adding to the glucose level in your blood and providing fuel for any cancer cells that may be present.
Most fruits contain fructose. Berries, though, are relatively low in sugars (and starch), and very rich in beneficial nutrients, so they are highly recommended.
Starches are large complex molecules made up of thousands of glucose molecules joined together. The arrangement of these glucose chains varies with the food. But all grains and similar starchy foods, like potatoes, starchy root vegetables and bananas (which also contain sucrose), have the same glucose/starch composition. It’s also similar in starchy above-ground vegetables, but these contain much less starch than root vegetables, as well as much more fibre and substantial amounts of many vital nutrients.
¼ cup desiccated coconut
6 whole walnuts, shelled
1 oz ground blanched almonds
2 Tbsp pumpkin seeds
1 Tbsp whole linseeds (flaxseeds)
½ cup tinned coconut milk
½ cup hot water
1 tsp ground cinnamon
1 handful blueberries
Place all ingredients, except the berries, in a food processor; blend and then scatter the blueberries on top. You can add sweetener if you like.
Almond coconut pancakes
Serves 4 (or 2 with leftovers)
Whenever you make these pancakes, you can make at least a double portion and save the rest for snacks as wraps, or keep them in the freezer for another breakfast.
1 tsp ground cinnamon
½ cup desiccated coconut
1½ cups ground blanched almonds
½ tsp baking soda/bicarbonate of soda
¼ tsp sea salt
1 cup tinned coconut milk
3 large eggs, organic orfree-range
2 Tbsp (solid) coconut oil
1 Sift dry ingredients and mix together.
2 In a separate bowl, whisk the coconut milk and eggs together.
3 Add the dry ingredients and mix thoroughly.
4 Heat coconut oil in a frying pan, pour in the batter and cook for 2–3 minutes on each side.
Foods to fight cancer
An anticancer diet needs to include a variety of foods to tackle the entire cancer process—from delivering a full spectrum of minerals/vitamins and boosting the immune system to oxygenating and attacking cancer cells, and reducing inflammation.
The most important foods in any cancer diet are plants. If you choose a colourful rainbow of vegetables and fruit, you optimize your ability to overcome cancer with a wide range of anticancer nutrients and phytonutrients, chemicals produced by plants as part of their means of survival.
The constant biological challenge of exposure to direct sunlight and ultraviolet rays all day long led plants to create powerful free-radical-scavenging antioxidant polyphenols to protect themselves. When you eat a diet rich in fruit and vegetables, you harness the powers of these phytonutrients into our diet.
The level of phytonutrients in any plant varies, depending on the pecies, soil conditions and many other environmental factors, although research
shows that organic plants have more phytonutrients than non-organic ones.
Phytonutrients are powerful protectors and fighters against cancer. They contain antioxidants to quench free radicals, anti-proliferative nutrients to slow tumour growth and agents that stimulate the immune system.
All dark-green leaves
Two of the best are kale and nettles. Kale has the highest levels of ‘good-for-you’ nutrients among green leafy vegetablesper calorie of energy. In addition to the wide array of vitamins and minerals, researchers have found 45 antioxidant, anti-inflammatory and anticancer nutrients in kale.1
Nettles are highly alkalinizing and rich in minerals; they can also help purify the blood. In addition to being a potent antioxidant, nettles have immune-boosting, anti-inflammatory and antifungal properties.
Other important greens include watercress, parsley, dandelion, barley grass, wheatgrass, spinach, rocket, Chinese leaves and chard.
Plan to have as many varieties, according to season, in store as possible. Choose from asparagus, celery, Brussels sprouts, cauliflower, cucumber, fennel, green and red cabbage, peppers (red, green, yellow and hot), courgettes, tomatoes, parsley, kohlrabi, lettuce, leeks,turnips, avocados (actually a fruit), carrots and beetroot.
These are all good sources of minerals and vitamins. Brown seaweed has anti-oestrogenic effect sand may help to stop the growth of breast cancer.2 Fucoidan, found inkombu and wakame seaweeds, helps to promote cancer-cell death and also stimulates the immune system.3 Alginate, found in sea vegetables like nori, kombu, wakame, arame and dulse, is a natural absorbent of radioactive elements, heavy metals and free radicals. Use them in soups
Garlic promotes blood circulation and the growth of healthy gut flora; it also eliminates unfavourable bacteria and yeasts as well as toxins from the body. Use garlic daily by adding it to juices, soups and salad dressings. Try slow-roasting the whole bulb, then squeeze out the sweet, soft garlic flesh and toss with steamed vegetables.
Meat, fish, eggs and milk
If you decide to include meat and fish in your diet, there are two key considerations: quality and quantity. Meat quality depends on the life the animal led before it was killed. There is a vast difference between eating the flesh of a wild deer and a non-organic chicken, reared in an intensive farming system, which has been bred to develop quickly, reaching slaughter weight in just 42 days. These birds spend their entire life indoors, and are routinely fed antibiotics and other antimicrobial agents. In addition to those drugs, there will also be pesticides, herbicides and other toxic agents used in raising their feed crops.
If adding a little meat in your diet makes you feel better, to limit toxins, choose organic and eat small portions.
The most nutritious fish are wild-caught, small, oily fish like sardines and herrings. Wild Alaskan salmon is another possibility and superior to farmed salmon, which are prone to parasites, bacteria and viruses.
Organic eggs contain high-quality proteins, fats, vitamins, minerals and antioxidants. Exceptionally easy to digest, they provide a wonderful boost to the immune system. Raw eggs are nutritionally superior to cooked ones, but if you find their texture a problem, it’s easy to pop them into a smoothie.
Modern ways of producing milk—pasteurized, semi-skimmed and homogenized—all have negative effects on our health. In general, it’s prudent to avoid all dairy products. However, from time to time in some people, there may be benefit from small amounts of organic, raw, unpasteurized kefir and curd cheese.
These include: olive oils; any omega-3-rich oils like fish, hemp and flaxseed oils; coconut oil; avocados; and oily fish.