Nutrition - Insulin growth factor (IGF-1)

Friday 04 May 2018

This week I am going to look at something called  Insulin growth factor or IGF-1. It is a bit of a scientific blog this week, I hope you follow it and it makes sense to you – if not then please let me know and I can provide a further breakdown for you.

The subject of IGF-1 is always of great interest to me, and is a regular topic of conversation from visitors that I meet and many books emphasise the importance of understanding it. I have quoted it myself in several blogs so I thought this week it would be worth having a look at it in detail to see what all the fuss is about.

So what is IGF-1?
It is the Human growth hormone also known as Somatotropin. It is a simple hormone, similar to insulin, produced by the pituitary gland in the brain and passes in the bloodstream to the liver where it is converted into two growth factors DGF1 and 2. These carry messages to other parts of the body to stimulate growth by making your cells divide at a faster rate. It is produced during sleep and is found primarily in prepubescent children, it’s production falls dramatically with age as we stop growing. Its primary function is to stimulate growth and to help bones to grow. It also helps to build and repair muscle tissue in adults and assists in the transport and utilization of protein.

What does IGF-1 mean for us?
IGF-1 is not peculiar to humans but is found in all animals and in milk. If we think about it milk is the only food used for the weaning process, hence the animals and we grow rapidly during the first 6 months or so of life. Therefore it would seem logical that the more animal protein and dairy foods that we eat then the higher our levels of IGF-1 will be and consequently our cells will be stimulated to grow. If our cells are stimulated to grow the cells would divide more rapidly, and it would indicate that this would be true for healthy cells as well as cells that are damaged.

This has been the findings of multiple studies, including many completed by professor J Holly from Bristol university faculty of medicine who is a world leading expert In IGF-1. Another study in 2004 reported in the European journal of Clinical Nutrition also concluded that IGF-1 from milk consumption can cause a significant increase in IGF-1 levels in humans by as much as 61%. In 2008 the BBC news channel reported similar results focussing on prostate cancer. The findings have also been supported by Cancer Research UK and by the cancer programme of the commission of European communities. I could quote many, many more studies and I could find nothing to contradict any of this.

So quite compelling.

IGF-1 and insulin levels
It would also appear that there is also a link here with insulin levels. Insulin as we know is produced by the pancreas to bring levels of sugar in the blood down to a normal level when it becomes raised after eating sugar or sugary foods.  When insulin levels are high this seems to stimulate IGF-1 levels and an increase in oestrogen levels. Could this then be the answer, to eat the animal protein but keep the sugar levels down and as a result the IGF1 would be lower?

This is all getting very complicated isn’t it!!

Where does this leave us? Well as always I believe in balance. I do know many people with cancer that are committed to avoiding animal protein particularly dairy foods because of the research that they have done and I am sure that this is a good thing. But if you find it difficult to cut out meat and dairy then the key is to balance the amount that you eat by including some of the non meat forms of protein like peas beans and lentils. Perhaps having 3 or 4 days a week that are meat and dairy free. This is not nearly as hard as it appears. I can think immediately of lentil soup or beans on toast, or hummus on oatcakes or beans casserole and rice or a vegetable curry and rice. What are you thinking so far? According to the evidence not only will this prevent the overall levels of IGF-1 rising but bring ‘balance’ into the diet.

If this seems all too much and you are used to a diet high in animal foods then try and balance this by including a high intake of fresh vegetables and some fruit to get the health benefits that they provide.

Interestingly exercise helps to reduce IGF-1 because when we exercise we produce endorphins which have been shown to reduce levels.  And of course, remembering the link with insulin and its effect on IGF1. Keeping blood sugar levels more even by avoiding high sugar foods may be an added bonus.

I have added a couple of my monthly recipes You may like to try these as alternatives to meat as they contain the vegetable sources of protein.

Shepherdless pie A healthy alternative to the traditional shepherds pie. Very economical to make.
2 tbsp oil
2 onions
1 large leek chopped
3 carrots diced
400g tin tomatoes
Half pt. vegetable stock
2 tbsp tomato puree
4 oz. red lentils
2 oz. brown rice
2 tbsp green pesto

1 kg. Potatoes
1 bunch spring onions finely chopped
4 fl oz. milk
Grated nutmeg
4oz. cheddar cheese (optional)

  1. Heat oil and fry onion till soft, add leek and carrots. Cook 5 mins.
  2. Stir in tomatoes, stock, lentils and rice. Simmer for 20 mins or until rice is soft. Stir occasionally.
  3. Peel and steam potatoes until tender.
  4. Put spring onions, nutmeg and milk in a small pan and heat gently to make an infusion.
  5. When potatoes are cooked mash and add milk infusion to make a smooth mash.
  6. When lentil base is cooked stir in pesto. Put lentil mix in an oven proof dish.
  7. Top with potato mash and sprinkle over cheddar.
  8. Bake in a moderate oven for 30 mins till crisp and golden.

Quinoa stew with squash, prunes and pomegranate.
This is a dish that makes a complete meal as the quinoa is rich in protein, the vegetables rich in vitamins and minerals and the ginger aids digestion. It is light but satisfying.

1 small butternut squash, peeled deseeded and cut into cubes
2 tbsp olive oil
1 large onion peeled and thinly sliced
1 large clove garlic sliced
1 tbsp of fresh root ginger grated
1 tsp of curry paste
200g of quinoa
5 large ready to eat prunes roughly chopped
juice of 1 lemon
1pt. vegetable stock
seeds from 1 pomegranate
fresh mint leaves to garnish.

  1. Heat the oven gas 6/elec 180'C. Put the squash onto a baking tray and sprinkle over 1 tbsp of olive oil, season and put to roast for about 35 min.
  2. Meanwhile in a large saucepan put the remaining oil, garlic, ginger and onion and cook for about 10 min, stirring constantly. Add the spices, quinoa and cook for another minute making sure that the quinoa grains are coated.
  3. Add the prunes, lemon juice and stock and bring to the boil, reduce to a simmer for about 25 min till the ingredients are tender.
  4. Stir the roasted pumpkin through the stew and just before serving put the pomegranate seeds on the top and then the mint.



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