We read and hear a lot about high fibre diets a how positive a lifestyle change they can be but have so far failed to act. With 82% of UK men (aged 55 to 64) and 70% of women (aged 65 to 74) either overweight or obese, now is the time to refocus your efforts and take the steps that will safeguard your midlife health.
How are adults adapting to a high fibre diet in middle age?
The word fibre, conjures up all sorts of negative connotations. However, this nutrient is in fact one of the most fascinating with an abundance of high quality research to back up its many health benefits.
In light of these proven health benefits could fibre be the secret weapon every mid-lifer needs to know about in order to future-proof their health.
What is fibre?
Dietary fibre is a term used to describe plant-based carbohydrate foods which cannot be digested (unlike sugars and starches) in the small intestine and so make their way to the large intestine or colon.
The two main categories of fibre include:
Soluble (oats, peas, potatoes, beans, apples, citrus fruits, barley)
This type of fibre dissolves in your digestive system to form a gel-like substance which is softens stools so they’re easier to pass.
Insoluble (wheat bran, wholegrains, cereals, seeds, nuts)
Insoluble fibre doesn’t dissolve in the gut and so can’t be digested. This means it adds bulk to your stools, and so helps food to be pushed through your digestive system.
Despite these definitions high fibre diets usually contain a combination of both soluble and insoluble fibre and it’s eating more overall which is the most important thing.
How much fibre do we get in the diet?
UK guidelines recommend that we eat 30g of fibre daily however the latest National Diet and Nutrition Survey (NDNS) has shown that only 12% of men and 6% of women manage to achieve this while average intakes are around a third of this recommendation2. The majority of fibre in the UK diet comes from bread, pasta, rice, pizza and other cereals according to the NDNS even though most people choose white over brown varieties of these foods.
What does the research say about fibre and health?
A comprehensive study commissioned by the World Health Organisation to help inform the development of recommendations for optimal daily fibre intake was published in the Lancet a few years ago3.
This research suggested that eating at least 25g to 29g of fibre each day led to a 15-30% decrease in all-cause mortality and cardiovascular related mortality when comparing those who ate the most against those who ate the least. Consuming fibre-rich foods also reduced the incidence of coronary heart disease, stroke, type 2 diabetes and colorectal cancer by 16-24%. The same study also found that increasing fibre in the diet was associated with both a lower bodyweight and lower levels of cholesterol (key risk factors for heart disease) according to an analysis of the available clinical trials.
According to this same study it was shown that for every 8g of fibre eaten per day, total deaths and incidence of coronary heart disease, type 2 diabetes and colorectal cancer decreased by 5-27%. While 25g to 29g per day was considered adequate the data from this survey suggested that higher intakes could provide even greater protection.
Fibre and diabetes
The amount of fibre in the meals you eat has an impact on blood glucose levels and being overweight is a well-established risk factor for type 2 diabetes. A large study published in the journal Diabetologia involving over 26,000 people found that intake of total and cereal fibre was associated with a lower risk of type 2 diabetes and that this association may be the result of body weight4.
Fibre and gut health
Certain fibres are regarded as prebiotics and include inulin and fructooligosaccharides which help the bacteria in your gut to flourish. Prebiotics help the gut to produce nutrients for colon cells such as short chain fatty acid which promote a healthy digestive system. Foods rich in these fibres include bananas, Jerusalem artichokes, oats and raw onions and garlic. Resistant starches also act as prebiotics and these are formed on foods such as pasta rice and potatoes after they have been cooked then cooled. These foods are not a good option for everyone as those suffering with irritable bowel syndrome (IBS) may benefit from avoiding such foods in accordance with the FODMAPS diet5.
Fibre and digestion
It’s widely understood that the key role of fibre in the diet is to maintain a healthy digestive system. Good digestion is bedrock to health and it’s in your gut that food is broken down, nutrients are absorbed and delivered around the body and where waste is removed.
Foods such as oats, barley, rye, beans, lentil, bananas, pears, apple, carrots, potatoes and golden linseeds are particularly rich in soluble fibres. These fibres are made from the parts of plants that absorb water such as cell walls and gums that hydrate your intestines making stools soft, which can be beneficial when suffering with constipation.
Foods particularly rich in insoluble fibres include wheat bran, dried fruit, corn, wholegrain cereals, wholegrain bread, nuts and seeds. These types of fibres are often referred to as roughage which passes through the gut without being broken down and helps with digestive transit by providing bulk and stool size.
Fibre and heart health
A large review of 27 studies published in the American Journal of Epidemiology concluded that maintaining a high fibre diet was associated with a lower risk of death including cardiovascular disease, diabetes and cancer. This study also showed a 10% reduced risk of disease for every 10g increase in fibre per day6.
Oats have been a key focus of research around heart health as they contain a type of soluble fibre called beta-glucan. This type of fibre swells in the gut to form a thick gel that binds to excess cholesterol and cholesterol like substances to prevent their absorption and removes them from the body as waste7. Lowering cholesterol is helpful in reducing the risk of heart disease.
Fibre and cancer
The World Cancer Research Fund (WCRF) has estimated that 45% of bowel cancer cases could be prevented through adoption of high fibre diets, physical activity and weight. Whilst no food alone is going to prevent you from getting bowel cancer the most up to date research has shown that a high fibre diet of three servings per day (90g) of wholegrains (brown rice, buckwheat, barley, bulgur, millet, oats) reduces the risk by seventeen per cent8.
High fibre diet and weight loss
Fibre is considered as being helpful for weight loss as it bulks out the diet and promotes satiety by slowing the breakdown of carbohydrates in the gut, which also has a moderating effect on blood glucose levels. It’s also well understood that maintaining a healthy body weight can help to reduce the risk of developing osteoarthritis10.
There’s no doubt that a high fibre diet has a positive impact on health and many of the protective effects linked to this nutrient are associated with the key areas of health that concern middle aged adults. Increasing your intake of fibre to meet the recommended daily intake of 30g a day is a beneficial way to protect your health and can be achieved by making simple changes to the foods you choose to eat. If you struggle to get enough fibre in your diet then supplements are available to help boost your intake such as Healthspan Easyfibre Inulin which also acts as a prebiotic in the gut (£12.95 for 450g tub).
References
- Attitudes_Towards_Dietary_Fibre_on_a_Multicultural_Basis_A_Fibre_Study_Framework
- gov.uk/government/statistics/ndns-results-from-years-9-to-11-2016-to-2017-and-2018-to-2019
- pubmed.ncbi.nlm.nih.gov/30638909/
- ncbi.nlm.nih.gov/pmc/articles/PMC4472947/
- ncbi.nlm.nih.gov/pmc/articles/PMC4918736/
- academic.oup.com/aje/article/181/2/83/2739206
- academic.oup.com/nutritionreviews/article-abstract/69/6/299/1815168?redirectedFrom=fulltext
- wcrf.org/dietandcancer/colorectal-cancer
- pubmed.ncbi.nlm.nih.gov/31174214/
- sciencedirect.com/science/article/abs/pii/S0271531700001640?via%3Dihub
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About the Author / Rob Hobson
Rob Hobson is a consultant nutritionist working with wellbeing supplement brand Healthspan. Rob also works with private clients and can be found at www.robhobson.co.uk
