Why Age?

Constipated Nation

“…If you pass small stools, you have to have large hospitals.”

Dennis Burkitt(1911-1993) Surgeon, medical researcher, and missionary

Burkitt knew a lot about stools, especially African ones. The tenacious Irishman, who lost an eye aged 11 did not let obstacles keep him from his goals. One of those goals was to take his Presbytarian missionary zeal to Africa where he treated hundreds of thousands in mission hospitals and discovered the geographically-specific lymphoma that bears his name.

It was bowel habits that concerned him most, and he must have observed many motions to conclude that the East African stool was larger, softer, and passed with no discomfort compared to the mean Western stool.

This led him to publish his 1979 bestseller - “Don’t Forget Fibre In Your Diet”   and focus Western attention on the link between dietary fibre and reduced risk of bowel cancer.

Colorectal cancer, as we call it today is a pernicious killer.

According to the latest available Australian figures of 2001, Colorectal cancer is the most commonly reported and is responsible for 13% of all cancer deaths. Only lung cancer causes more deaths from cancer(19%).

Each year there are 12,600 new cases and 4,700 deaths. 1 in 21 Australians develop Colorectal cancer (CRC) over a lifetime and it’s estimated that 29,058 life-years are lost from premature deaths under 75 years of age.

It’s a disease whose risk rises after age 40 and rises sharply after age 50. 1 in 10 men and 1 in 15 women develop it by age 85.

Burkitt did not see a single case of it in his decades in Africa and also reported that ”In 20 years of surgery in Africa I had to remove exactly one gallstone.”

He concluded that the African diet was the key to preventing CRC and this has been borne out by later studies that show Africans who move to the West and adopt Western diets suffer CRC at rates expected in Western populations.

Africans are not protected by genes but by diet.

Burkitt surmised that fibre in the African diet was the key and kicked off the whole fibre obsession that gripped us in the 70s, 80s and 90s. Certainly fibre is important but it turns out African diets are not especially high in fibre after all and another fibre-like substance is the key.

“Western diets are so low on bulk and so dense in calories that our intestines just don’t pass enough volume to remain healthy” DB

Nevertheless, he was onto something and that something is known today as Resistant Starch (RS) Medico-nutrition pundits had been aware of the 10 % residue in the starch we eat that reaches the colon undigested but had dismissed it as “empty calories” and “useless.”

They couldn’t have been more wrong.

In the 80s, serious research began on it that continues today and elevates RS to a status alongside fibre as a key in CRC prevention.

Starch is carbohydrate, in long chains of sugars. Some is easily digested, like a highly-refined slice of white bread. Other types are usually less processed and locked up in nature’s packaging like the kibbled wholegrains in multi-grain bread.

After being churned into tiny particles in the stomach, food is broken down by chemical digestion in the small intestine. Some foods, however, resist this process and reach the large intestine (colon) intact and are broken down by bacterial decomposition. Bacteria in the colon cause fermentation and several by products of this process fuel the body and the cells that line the colon walls.

One of these short chain fatty acids is butyrate - a substance that has researchers very excited due to its anti- inflammatory and anti-carcinogenic properties. Butyrate applied to cancer cells in a dish stops them in their tracks.

RS also reduces glycemic impact of foods as we age - that is it smooths out the fluctuations of energy we get from eating, and increases insulin sensitivity.

RS promotes the growth of healthy colonic bacteria and the short-chain fatty acids it produces are absorbed into the bloodstream where they lower cholesterol.

Where do we get Resistant Starch?

There are four sources:

• Seeds, legumes and unprocessed whole grains
• The naturally granular, high-amylose form in a firm banana and other unripened fruit (eg green papaya salad)
• Starch cooked and allowed to cool - e.g. cold potato, pasta and rice dishes.
• Starch chemically modified to resist digestion.

Potatoes, pasta, beans - these don’t sound like unattainable foods yet a 12-nation study mentioned on ABC Radio National’s Health Report established a strong link between low RS intake and colon cancer. Unfortunately Australians rated as one of the lowest RS intakes and correspondingly one of the highest incidences of CRC.

One of the comments I hear a lot is that people don’t eat carbohydrates after 12, or 3pm, or 6pm or whenever because “they make me feel so bloated”. What they really mean is “they fill me up” with starch and fibre and that turns out to be a very good thing in preventing CRC.

Many researchers now feel RS should be categorised as fibre and the US National Academy of Sciences’ Institute of Medicine recommend we get 38g and 25g per day for men and women respectively.

The CSIRO says we should get at least 20g of RS per day. Australians currently consume only 5-7g per day.

“The only way we are going to reduce disease is to go backwards to the diets and lifestyles of our ancestors.” DB

Talking of bulky starch in the intestines reminds me of a stay I had in a traditional village on Buka Island, near Bougainville in the 1970s. Amongst other occurences like having water poured on me to protect me until I returned, and being woken every dawn by the noisy pigs who slept under my hut, one thing stands out, and that was breakfast.

The first morning I was brought an enamelled tin dish piled high with boiled, peeled kaukau, or sweet potato. I counted 8 or 10 of these purplish door-stoppers and sat watching them steam. My host came in and asked when I would eat my breakfast. I’d been waiting politely for the others because who eats this many spuds on their own?

It turns out my lean, muscular and fit hosts did -every day. Dennis Burkett never got to examine their stools but I’m sure he would conclude they were more than adequate to prevent cancer.

Legumes (beans, peas and lentils) top the RS lists. One half-cup of cooked beans (equivalent to a serve of baked beans) yields 9.8g of RS. A firm banana has 4.7g and an average cold, cooked potato dishes up 3.2g.

Cooking and cooling rice, potato and pasta subjects it to a process called “retrogradation” which converts some of the gelatinised starch into a crystalline form that resists digestion.

John Burn is the Professor of Clinical Genetics at Newcastle University in the UK and he told ABC’s Health Report of his disappointment in trials that fed subjects fibre that didn’t work to reduce CRC. The same thing happened when they were fed RS but rats fed both produced high butyrate levels. He concluded that more fibre pushes more RS through the gut and reaches more cells with its anti-carcinogenic properties.

Natural foods from the plant kingdom supply both in tasty packages and are clearly the way for us to go. It would be folly to wait until chemists perfect the high RS grains and other food products they are currently working on.

It would be an equal folly to adhere to diets like low-carbohydrate and GI-based diets that scare us away from the starchy foods essential to prevent cancer. Look for a fairly savage critique of the whole GI “system” in my next post.

Oh, and if you are worried about the gas caused by fermentation of RS in the colon, don’t. Your system and intestinal flora will adjust to African overload after a while and your gut will be happier and healthier.

UPDATE: The Indian manufacturer of my “Ayurvedic” “natural” toothpaste did eventually respond to my query as to why they put suspected carcinogens in their product, and supplied reams of studies to support their harmlessness, but too late. I now use charcoal tablets crushed and mixed with soda bicarb for a cheap, effective and pleasant tooth scrub. It’s messy but it works and no nasties!