A comment on: Eat, fast, and live longer

A BBC Horizon programme presented by Michael Mosley. This programme explored the role of diet and nutrition in ageing.

At Cornell University researchers are studying a genetically modified mouse strain, which exhibits longevity (longer life) with a calorie restricting diet. This work has been extended to human study at Fontana Washington University. Here, they have set up a long-term study of dietary intervention. The principal investigator was quite confident that the people undertaking this approach are a new species. I doubt this very much. Participants are restricted to 1,900 calories a day, usually eaten at breakfast as a huge bowl of fruit. Time will tell if this approach does indeed lead to a longer life, but if positive results were needed, age-related tests were conducted. These included assessment of balance and reaction times, as well as blood tests for metabolic markers, and levels of body fat. Mr Mosley’s assessment was pronounced as ‘not good for his age’, but the balance and reaction time tests are both subjective and can be improved with practice. More alarming was the absolute declaration that following the calorie restriction programme for just one year will result in a reversal of disease progression. In fact, the researcher went on to say that after following the diet for 10 years, J (a volunteer) would never develop a stroke or heart attack.

The truth is that in order to fully assess the risk of death from cardiovascular disease or cancer, we would need to sequence every bit of DNA in every person in the world, follow those people from birth to death, and analyse their lifestyles for diet, exercise and environmental factors. Then, we might be able to say who will die from heart attack, or not. Some research, including my own, has identified important genes, which contribute to the risk. I have also found out that the normal variation of these genes, interacting with certain environmental factors, like stress, injury or infection, can affect the way the body responds. So, you see, it is a very complex picture, and not simply down to calorie restriction.

Professor Valter Longo, from the University of Southern California does add some science to the discussion. His research centres around an important metabolic protein, Insulin-like Growth Factor 1 (IGF1). Reduced levels of IGF1 in the blood have been associated with slowing cellular metabolism (the so called ‘go,go’ mode), increased repair of DNA damage and protection from age-related illness, in a genetically modified laboratory mouse strain.

Ex vivo research (that is, in cells taken from the animal’s body) have shown that cells in ‘go’ mode are more susceptible to cancer, as they do not show efficient cellular repair. Studies in humans have shown that calorie restriction together with a low protein diet leads to reduced circulating IGF1 levels in the blood. The mechanism of action for this is that as glucose (blood sugar) is depleted in the body, the body (in particular the large muscles) start burning fat for fuel. The liver stops or slows production of IGF1, pushing the cells into repair mode. This is not a happy state of affairs for the body of an active man or woman. Prolonged fasting can be dangerous and should only be done under medical guidance. Extreme metabolic changes can occur with short fasting protocols too. Proponents of the alternate day fast or the 5-2 fast regimes often report that they are unable to exercise on fast days due to dizziness and weakness.

The main tenet of the piece is portion control, which I endorse. It’s no secret that if you eat less and move more, your body will be stronger and healthier, provided of course that you maintain adequate nutrition. And the emergence of these fasting diets for sustained weight loss should be viewed with some skepticism.

There was no discussion about the role of our genetic make-up and ageing, or longevity. Yet, many of us will know people who live long and when asked the secret, simply say eat well, exercise a bit, and have fun.

I'm not a sceptic, I'm a scientist

I read the papers every day and I never cease to be amazed at the total lack of credibility of the health stories. This is across all the papers, because it's what we, the public, are told it's what we want to read. Well, it's not what I want to read. And I believe that many of us glance through the stories and then get on with our balanced diet, with a bit of exercise and a healthy, positive approach to life. Or do we? I'd like to think so, but the sheer volume of these stories mean that at some point, we're going to stop and read on and give them more than a cursory perusal.

Two such stories caught my eye this morning. The first is about a diet based on our genes. To be specific, a genetic test based on the normal variation of seven genes. These seven genes out of thousands of genes have been picked because of their role in metabolism and were decided upon by researchers working on diabetes type 2. Diabetes is a serious health condition and genetically speaking is a complex multi-factorial disease. That means that it's not just what you do or don't eat, it also depends on your genetic make-up and how your genes interact with your environment (I have written more on this here). And there are certainly more than seven genes involved. A lovely blonde woman is shown as having lost loads of weight and, they say, dieters using this diet have kept the weight off. Isn't it more likely that people who are supported and encouraged on diets in these studies have more success at weight loss than those who diet on there own?

The second story is a re-hash of the old don't eat processed meat story, you'll get cancer. We know. But a bacon sandwich or a sausage roll occasionally is both delicious and can be part of a balanced diet. We are enlightened enough to understand the health disadvantages of eating a high fat, processed food diet, but it is after all our choice. And I choose to eat bacon if I want to, I don't eat it every day. I also eat broccoli and oily fish and brazil nuts for selenium. And I may or may not get cancer or heart disease.

The point is, we have made huge advances in genetics but we do not know everything about how our genes work. It is something that has potential in science and medicine and I wholly support the scientific study in this area. But please don't give up a healthy, balanced lifestyle in the hope that nothing bad will ever happen to you. 

Follow @Shackleford_LB

I'm not a sceptic, I'm a scientist

I read the papers every day and I never cease to be amazed at the total lack of credibility of the health stories. This is across all the papers, because it's what we, the public, are told it's what we want to read. Well, it's not what I want to read. And I believe that many of us glance through the stories and then get on with our balanced diet, with a bit of exercise and a healthy, positive approach to life. Or do we? I'd like to think so, but the sheer volume of these stories mean that at some point, we're going to stop and read on and give them more than a cursory perusal.

Two such stories caught my eye this morning. The first is about a diet based on our genes. To be specific, a genetic test based on the normal variation of seven genes. These seven genes out of thousands of genes have been picked because of their role in metabolism and were decided upon by researchers working on diabetes type 2. Diabetes is a serious health condition and genetically speaking is a complex multi-factorial disease. That means that it's not just what you do or don't eat, it also depends on your genetic make-up and how your genes interact with your environment (I have written more on this here). And there are certainly more than seven genes involved. A lovely blonde woman is shown as having lost loads of weight and, they say, dieters using this diet have kept the weight off. Isn't it more likely that people who are supported and encouraged on diets in these studies have more success at weight loss than those who diet on there own?

The second story is a re-hash of the old don't eat processed meat story, you'll get cancer. We know. But a bacon sandwich or a sausage roll occasionally is both delicious and can be part of a balanced diet. We are enlightened enough to understand the health disadvantages of eating a high fat, processed food diet, but it is after all our choice. And I choose to eat bacon if I want to, I don't eat it every day. I also eat broccoli and oily fish and brazil nuts for selenium. And I may or may not get cancer or heart disease.

The point is, we have made huge advances in genetics but we do not know everything about how our genes work. It is something that has potential in science and medicine and I wholly support the scientific study in this area. But please don't give up a healthy, balanced lifestyle in the hope that nothing bad will ever happen to you. 

Follow @Shackleford_LB

IT'S NOT WHAT YOU EAT...BUT IT DOES HELP

I heard Polly Noble on telly this morning. She makes a lot of sense but changing your diet and lifestyle after a cancer diagnosis cannot shrink tumours. Having a sensible, balanced diet and an active, happy lifestyle will help to protect against many but not all illnesses, and cancer can strike anyone. Polly has added to the debate about chemotherapy treatment with her new book, but the oncologists have heard and seen it all. Be prepared to ask the difficult questions about the expected outcomes from your cancer treatment.

If I'm not making myself clear, it's because I'm trying to be sensitive and open-minded, but to be honest, there just isn't the science to support the argument for nutrition treating tumours. There, I've said it, and I'm not sorry. Tumours need to be cut out or reduced in size, and there are almost endless combinations of surgery, radiotherapy, chemotherapy and biological treatements, for all different cancers for the oncologists to try. 

Holistic and alternative therapies are important, though, because they very often sit alongside the conventional therapies, to support patients and their families. Ideas with food are so important because they give everyone something to do and think about, other than cancer diagnosis and treatment. Sharing a healthy meal as a family gives a sense of normality.

Back to Polly's approach. Polly recommends a low- or anti-inflammatory diet. Now, this isn't entirely wacky. Sufferers of irritable bowel syndrome, for example, know which foods contribute to a flare-up of their condition. But it's easy to see the connection between food and irritable bowel. What is less obvious is the link made by Polly between inflammatory foods like refined foods, high salt, sugary foods etc, and say lung cancer. Yes, cancer is an inflammatory condition, but it is associated with a chronic low-level rise in markers of inflammation in the blood after cancer has already developed. So, eating an awful lot of oily fish and blueberries may reduce these markers of inflammation but won't affect the cancer.

Of course, these foods are really good for us and should be included in every healthy diet, but don't put all your hopes on a wonder cure for cancer. It's almost always hard work beating cancer. Use all the resources you can. Eat well, live well, surround yourself with positive people, find your inner peace, see yourself well, but don't give up on conventional treatment.

You are all in my thoughts.

Follow @Shackleford_LB