Scientists have identified the most crucial period of human nutrition – and it’s the first one thousand days of life. Professor Alan Jackson, professor of human nutrition within medicine at Southampton University, talks about the significance of early feeding, the role of diet in managing chronic illness and the threat from public enemy No.1 when it comes to health eating – sugar.
Someone who survives to the age of 80 notches up almost 30,000 days of lifespan. So you might thing that leaves plenty of time for the body to make up for any nutritional deficiencies it might ensure in the early stages of life.
But there is now a consensus that the first 1,000 days of life – from conception to the age of two – are critical when it comes to laying the foundations for a healthy life. Professor Jackson, whose early career focused on tackling malnutrition in children, says science can now show that if the human body does not get off to a good start, it may never make up the difference.
‘If you grow well in childhood, your ability to cope with challenging environments is likely to be greater,’ he says. ‘But if you grow poorly in childhood, then you’re more likely to be vulnerable. That is why currently within the United Nations global system, there is this emphasis on the first 1,000 days of life – from the time that you are conceived to how you grow as a baby in the mother, how you grow as an infant and how your grow as a child particularly up to 2 years of age.
‘If there is a solid foundation of good growth and good health laid down in those first 1,000 days, then you are well set up for the rest of life. If that is not set down well, then you are is were ‘always trying to catch up’.’
Most of us, he concedes, have to do some catching up at some point. But for some the challenges are greater and this makes them more vulnerable to illness and disease when it comes along.
‘Quite clearly, growing during childhood is taking in food and depositing it as your own body tissue. The body has needs and those needs are in part determined by the genes you have. So the better able you can meet the needs of your body at whatever stage or time of development you are at, then the greater your ability to grow well and be more resilient.’
The question is then, to what extent are nutritional ‘shortfalls’ involved in the whole disease process? And how important is good diet in terms of preventing illness?
For the past decade, Professor Jackson has been working with the World Cancer Research Fund. It has focused on exploring the complex relationship between diet and cancer, highlighting the potential links between poor nutrition and several types of tumour.
‘The World Cancer Research Fund has invested a very considerable sum of money and carried out the largest systematic reviews in any part of medical literature,’ say Professor Jackson.
‘It’s quite clear that something of the order of at least 25 to 30 per cent of cancers are caused by nutritional considerations. As smoking declines diet, nutrition and physical activity will come to be the dominant determinants of cancer risk.’
So if diet can prevent, or at least reduce the risk of some potentially fatally illnesses, can it ‘cure’ them once they have set in?
‘It’s a challenging question,’ he admits. ‘We don’t know the answer.
‘My suspicion is that it might well do but that is probably the more important agenda going forward.’
He points to what he calls ‘forever’ conditions – chronic and incurable illnesses – that don’t go away but do respond well to good diet. Cystic fibrosis is one, phenylketonuria is another.
‘Children born with cystic fibrosis do extremely well and a part of that is ensuring that their nutritional health is maintained. So, it doesn’t sure disease in the sense of curing an infection or cutting out a tumour, but it cures the disease in terms of the process expressing itself as an inability to function well or normally.’
Knowing the effects of good diet is one thing. Putting it into practice is proving to be an altogether bigger challenge. Professor Jackson believes the real hurdle is getting everyone – from food manufacturers to consumers – to commit to radical change. And one of the biggest battlegrounds of late has been sugar.
It has emerged as public enemy number one in the healthy diet debate. But how big a problem is it really?
Professor Jackson says: ‘When you are talking about sugar, you are talking about sucrose. Biologically, sugars are an integral part of our metabolic machinery. For example our gastrointestinal tract and respiratory tract are protected because of the production of mucins. Most people would call that mucus but it is made up of mucins that form a physical barrier that keeps us healthy. Mucins are sugar related compounds.’
But dietary sugars are a completely different matter.
‘The clearest example is sweetened carbonated drinks which contain very large amounts of sugar for their volume and very little in the way of nutrients. Some young people consume very large quantities of sweetened drinks and therefore consume very large amounts of sugar and that is not good for them at all.
‘Then you have a variety of foodstuffs which contain rather a lot of sugar and by and large too much sugar limits the quality of your diet.’
Tackling the sugar crisis is not impossible, he believes. A good example of how it can be done is with salt, sugar’s predecessor as most-hated food ingredient.
Salt levels in processed foods have gradually been reduced because public health bodies worked closely with food manufacturers, rather than fight against them.
‘It was known that you could progressively reduce the amount in food gradually and the population wouldn’t know. In time they would end up consuming less salt. That is exactly what has happened. The consumption of salt now is significantly less that it was 15 years ago without anybody noticing.
‘The food industry has to a considerable degree honoured their reasonability and the UK is amongst the best in the world in terms of having achieved its salt reduction. It required considerable planning and effort in the set up to get agreement across the board – but difficult things take a long time.’
With a background in artificial feeding, Professor Jackson is just as interested in how proper nutrition can benefit those with gastrointestinal disease.
He is passionate about the need to invest in training for structured nutrition programmes and says it can lead to considerable savings in reduced hospital stays. But how and when is parenteral nutrition appropriate?
‘Well, if you take out someone’s gastrointestinal tract, then they have intestinal failure. That is absolute and they will need parenteral nutrition unless someone transplants their gastrointestinal tract. So parenteral nutrition is used in my book for intestinal failure, which may be acute, it may be chronic, it may be total, it may be partial, it may be reversible or it may be irreversible.
‘Therefore how likely you are to come of it is determined by which of those factors are at play. The most common form of intestinal failure is perioperatively, which is self-limiting and a short period of support gets people into their usual form of eating. But if someone takes out your tract you will be on it for life unless you are transplanted.
‘Those are the extremes. The challenges for clinicians is to help you make progress and it is impressive how, with decent parenteral support, patients who previously would have never been considered capable of coming off nutrition, have.
‘I have seen patients with very substantial intestinal resections that didn’t look like they would ever come off parenteral nutrition being able to, because the gut has adapted to cope better than it did previously. These people aren’t cured. But their bodies have responded to the insult and accommodated to do the best they can.’
By Pat Hagan
Professor Alan Jackson – Career at a glance.
‘I am basically a clinician and a paediatrician. I have spent my time looking at evidence for improved nutritional care and support of patients. Originally that was in children with severe malnutrition in the Caribbean and, since I came to Southampton in 1985, in terms of nutritional support of patients.
I worked very closely with Professor David Barker, understanding the nutritional determinants of the early origins of adult chronic disease.
Along the way I’ve done some molecular, cellular level work, clinical studies and population studies. And for the past 10 years I have been involved with the World Cancer Research Fund looking at the evidence in and around nutrition, physical activity and cancer.’