Is Fruit Bad for You?// written for dieteticallyspeaking

This is probably one of the most frequently asked nutritional questions, and the answer is NO.

The idea of fruit being bad for us has come from media articles focusing on its high sugar content. However fruit is high in a natural occurring sugar called fructose. Some studies have stated that fructose may have some negative effects on the body (1,2). These include high-blood pressure, potential decline in liver function and even a reduction to insulin response (2) However, these negative effects only occurred with excess fructose consumption. It’s also worth noting that the majority of studies used industrial fructose (sugar syrup, processed foods, and sugar-sweetened beverages). Therefore having fruit on a daily basis is NOT associated with these health issues (1-4)

colour bowlIf you drink a glass of water containing 3 tablespoons of sugar (the equivalent to a can of soda) your body would have a blood sugar spike. This causes large amounts of insulin to be released to help drop our blood sugar levels (4) However, this results in sugar levels dropping to below what they were originally (4,5). Because of this our body thinks it’s going into starvation and releases fat into our blood stream for energy and warmth (5). Studies have shown this does not occur with fruit.

Research has shown the cellular structure of the fruit is important for this (6,7). Let’s use an apple as an example. Sugars are effectively sequestered in the apples cell wall, which our digestive track has to break down before the sugars are released (8). This takes time. Therefore sugar is absorbed into the bloodstream slowly, giving the liver more time to metabolise (2,4,5,6).

Does Fruit Fill Me Up?

Studies have shown that sugar effects the hormones that tell our brains that we are full. In turn this results in us consuming more food than we need. However research has shown that fibre-rich fruit (fibre helps the cell walls remain intact) for example an apple, takes a longer time to chew and is therefore broken down more slowly (9) Resulting in the apple traveling far longer through the digestive tract, triggering the satiety hormones that tend to cluster further down the small intestine (1,2). The result is that you feel satisfied for a longer period of time compared to when we consume a low fibre, high sugar food like fruit juice or jelly babies (6,7)

A study in 2009 looked into how consuming preloads of apples in different forms (apple, applesauce, and apple juice with and without added fibre) prior to a meal influences satiety and energy intake at meal. Results showed that individuals consuming the whole apple had an increase in satiety compared to the applesauce or apple juice. The researches also added naturally occurring levels of fibre to the juice, however this did not enhance satiety. Overall the results suggest that solid fruit affects satiety more than pureed fruit or juice, and that eating fruit at the start of a meal can reduce energy intake. (8)

Food high in fibre, fat and protein are satisfying and keep us fuller for longer, so fruit is a great addition to a balanced meal to make it more filling, and a great idea for a satisfying snack is to combine a piece of fruit with a high protein food e.g. a handful of nuts, a piece of cheese.

fruitWhy is fruit juice different?

The metabolic effects of orange juice are very different than those of the fruit. Although orange juice does retain the vitamins, the fibre content is very different. (4,8) This is due to the juice processing. Fibre is usually filtered out, reducing its beneficial pro-satiety effects (3,6,8) The juicing process also results in the cell wall breaking releasing the sugar which will be dissolved in the juice. The sugar therefore is efficiently absorbed by the small intestine and enters the bloodstream quickly (6, 7). As stated previously this causes a rapid raise in your blood sugar levels and eventually causes a subsequent blood sugar “crash,” which in turn results in hunger. The recommended portion size is 150ml of pure fruit juice per day.

The Benefits of Fruit

Fruit has many proven health benefits. Regular fruit consumption has been associated with a lower risk of strokes, certain types of cancer early death due to a reduction in cardiovascular disease (3,5, 9,10) Fruits are packed with essential vitamins and minerals that our body requires to stay healthy. Fruits like berries are packed with antioxidants which help fight free radicals and reduce oxidative stress on the body (4). As stated previously, whole fruit is full of fibre, the daily reference value for dietary fibre is 30g/day. However research has shown the average UK adult consumes half that at 15g/day.

Fibre is essential for the health of our digestive system. Research has also shown a reduced risk in developing, bowel cancer, hear disease, stroke and even type-2 diabetes with an increase in fibre consumption (10)

So fruit is an extremely healthy food, and most people would benefit from consuming more fruit and vegetables each day. Remember that’s its best to consume whole fruit rather than juices to increase your fibre intake.

 

 

  1. Stanhope, K. L., Schwarz, J. M., & Havel, P. J. (2013). Adverse metabolic effects of dietary fructose: results from the recent epidemiological, clinical, and mechanistic studies. Current opinion in lipidology, 24(3), 198–206.
  2. Johnson, R.J., Segal, M.S., Sautin, Y., Nakagawa, T., Feig, D.I., Kang, D.H., Gersch, M.S., Benner, S. and Sánchez-Lozada, L.G. (2007) Potential role of sugar (fructose) in the epidemic of hypertension, obesity and the metabolic syndrome, diabetes, kidney disease, and cardiovascular disease. 86(4) 899-906. Am J Clin Nutr.
  3. Brown, L.., Rosner, B., Willett, W.W. and Sacks, F.M. (1999) Cholesterol-lowering effects of dietary fiber: a meta-analysis. 69(1):30-42. Am J Clin Nutr.
  4. Dauchet, L.., Amouyel, P., Hercberg, S. and Dallongeville, J. (2006) Fruit and vegetable consumption and risk of coronary heart disease: a meta-analysis of cohort studies. 136(10):2588-93. J Nutr.
  5. He, F.J., Nowson, C.A., Lucas, M. and MacGregor, G.A. (2007) Increased consumption of fruit and vegetables is related to a reduced risk of coronary heart disease: meta-analysis of cohort studies. 21(9):717-28. J Hum Hypertens.
  6. Stanhope, K. L., Schwarz, J. M., Keim, N. L., Griffen, S. C., Bremer, A. A., Graham, J. L., … Havel, P. J. (2009). Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. The Journal of clinical investigation, 119(5), 1322–1334.
  7. White J. S. (2013). Challenging the fructose hypothesis: new perspectives on fructose consumption and metabolism. Advances in nutrition (Bethesda, Md.), 4(2), 246–256.
  8. Flood-Obbagy, J. E., & Rolls, B. J. (2008). The effect of fruit in different forms on energy intake and satiety at a meal. Appetite, 52(2), 416–422. doi:10.1016/j.appet.2008.12.001
  9. Aune, D., Giovannucci, E., Boffetta, P., Fadnes, L.T., Keum, N., Norat, T., Greenwood, D.C., Riboli, E., Vatten, L.J. and Tonstad, S. (2017) Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality—a systematic review and dose-response meta-analysis of prospective studies, International Journal of Epidemiology, 46(3) Pages 1029–1056,
  10. SACN- Carbohydrate and Health Report https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf