So what’s the deal with fructose?
There’s much talk out there in recent times about fructose , in particular the negativity around it. Truth is, when eaten in excess fructose can have damaging effects on the body, and has been scientifically proven to contribute to chronic diseases including type 2 diabetes, heart disease, obesity and non-alcoholic fatty liver disease (NAFLD) (1). And whilst it is a naturally occurring substance, like anything we do have to be careful as to how much we consume. Because little do people know that it’s hidden in so many foods that they aren’t aware of!
Fructose is the major carbohydrate found in fruit, and whilst we do obtain some fructose from fruit and vegetables, a lot of the fructose consumed in the average diet is obtained from added sugars, with some of the worst sources being sucrose (also known as table sugar – sourced from sugar cane and sugar beets), high fructose corn syrup, agave nectar (which is often made out to be ‘healthy’ but actually contains more fructose than table sugar!!) and even honey. Fructose is found in most packaged foods, including breakfast cereals, cakes, biscuits, desserts, confectionary, soft drink, juices and even savoury foods. Believe it or not, much of the processed/packaged (and sometimes even ‘healthy’) food sold has some form of fructose added to it – particularly because it is very addictive, making consumers want to eat more and more!! Real the labels people!!
Carbohydrates come in many forms. Of the simplest are monosaccharides and disaccharides (also referred to as simple sugars. Monosaccharides consist of glucose, fructose and galactose, and disaccharides consist of sucrose (1 fructose and 1 glucose molecule), maltose (2 glucose molecules) and lactose (1 glucose and 1 galactose molecule). Our taste buds sense fructose as the sweetest sugars of all, leading to consumers becoming addicted to products, much like an addiction to a drug such as cocaine (2). Once different sugars enter our body, they undergo different metabolic pathways. Entering the bloodstream, fructose, unlike glucose cannot be metabolized by all parts of the body. Instead, fructose is directed towards the liver, where it replenishes liver glycogen stores and triglycerides are synthesised (1). Other end products include uric acid and free radicals (1). And what can happen next had the ability to cause harm – very high fructose consumption has the ability to raise triglycerides, which can build up in the cells of the liver and cause damaging conditions, particularly NAFLD (1). Furthermore, these triglycerides can be released into the bloodstream causing further damage by forming fatty plaques on arterial walls, contributing to the development of high blood pressure and heart disease (3). During the processing of fructose metabolism, two other metabolites are also released – uric acid, which has the ability to turn off nitric acid production (a substance that protects arterial walls), and free radicals, which can create all sorts of harm to the body including damage to cellular walls and structures, enzymes and genes (1).
Fructose was once a healthy part of the diet, obtained from mostly just fruit and vegetables. But the average amount consumed in Australia (and many other countries worldwide) has increased DRAMATICALLY over time. In the 1800s, the average person in Australia was consuming an estimated 1-2kg of sugar per annum, in the 1900s this increased to an estimated 5kg per a person per an annum, and in 2010 it raised to a whopping estimate of 50-65kg per a person per an annum (3). This is crazy!
So what can we do about? First we MUST start by cutting out ALL drinks containing sugar. This includes soft drinks, fruit juices (unlike fruit, there’s usually no fibre in these at all), flavoured milks and exercise drinks. Also cut down on adding sugar to your coffee and tea (this incudes honey, a little bit of honey every now and again is okay though – make sure you only use pure and unheated honey, which provides an abundance of nutriets!). These drinks contain empty calories which have no nutrient value whatsoever – they will just leave you thirsty for more. Attempt to cut out as much food containing sugar as you can by looking at the ingredients list on the packet. Many packaged foods have sugars added to them to make them taste better (especially low fat products). Be careful of other hidden names for sugar, examples include; sucrose (a combination of fructose and glucose), cane sugar, cane syrup, cane juice, agave nectar, high fructose corn syrup (HFCS), beet sugar, blackstrap molasses, golden syrup, coconut sugar, date sugar, date syrup, honey, maple syrup, fruit juice, fruit juice concentrate, grape juice concentrate (particularly added to balsamic vinegar), turbinado sugar and panela sugar. Head to this link for a further guide on deciphering hidden sugars.
And when it comes down to natural fructose intake, I usually say that we should aim for a max of 2 pieces of fruit a day. One serve equates to 1 piece of a medium-sized fruit (e.g. orange, apple, pear, banana), 2 pieces of small fruit (e.g. plums, apricots, kiwi fruit), or 1/2 cup of smaller fruit (e.g. strawberries, blueberries, blackberries, raspberries). Don’t forget that fruit contains an array of nutrients including “vitamins, minerals, fibre and phytochemicals” (5). These are essential to vital functioning, without them we create an environment where ill health can arise. Just remember not to overdo it. Take time to enjoy consuming food, savour the taste and appreciate the vitality it is providing you. You will be grateful in the long run!!
1. Skerrett, Patrick J. Is fructose bad for you? [Online] 2011. https://www.health.harvard.edu/blog/is-fructose-bad-for-you-201104262425.
2. Catherine Shanahan, Luke Shanahan. Deep Nutrition . New York : Flatiron Books , 2016.
3. Cousens, Dr. Gabriel. Fructose and Diabetes. Dr. Gabriel Cousens . [Online] http://treeoflifecenterus.com/fructose-and-diabetes/.
4. History of Sugar . No Fructose . [Online] http://www.nofructose.com/introduction/other-stuff/history-of-sugar/.
5. Eleanor Whitney, Sharon Rady Rolfes, Tim Crowe, David Cameron-Smith, Adam Walsh. Understanding Nutrition (3rd Edition). South Melbourne : Cengage Learning Australia , 2017.