Sugar intake, particularly in children, is a hot topic in the media these days. However, government data suggests that children are still far exceeding the maximum recommended sugar intake every day
Government recommendations are that sugar should account for no more than 5% of daily calories. When put into more practical terms this means 19g for age 4-6 and 28g for age 7-10 (28g is the equivalent of 7.5 teaspoons).
According to the National Diet and Nutrition Survey (NDNS) in 2016, the average was 13.4% for those aged between four and 10 and 15.2% among 11- to 18-year-olds. Sugar can be hidden in many foods particularly processed and ultra-processed foods and therefore keeping track of sugar intake can be difficult. There is concern about increasing rates of obesity in children which is very important. However, sugar intake does not just have an effect on weight, it also impacts cognitive health, immunity and energy levels, all of which are important for growth and development as well as long-term health and wellbeing. Many children within a healthy weight range are still consuming too much sugar.
Sugar and the gut
It has been well documented that the gut and the gut microflora play many essential roles in relation to maintaining health and wellness. Firstly the gut microflora are essential for the function of the immune system, 70% of immune tissue is located in the digestive system as ‘gut-associated lymphoid tissue’ or GALT. In addition, the balance of flora within the colon plays an essential role in stimulating and supporting the normal function of the GALT as well as modulating inflammation and supporting the integrity of the digestive lining.
Recent research has shown that the balance of gut flora is strongly associated with an individual’s ability to lose or gain weight and certain flora are related to an increased risk of obesity. High sugar intake has a significant effect on the microbiome(1) and can stimulate the overgrowth of undesirable bacteria and microbes. Studies have shown that a high fructose intake is related to an overall decrease in bacterial diversity and an increase in the Firmicutes/Bacteroidetes ratio(2), which is associated with increased weight gain and obesity(3.)
Brief overview of blood sugar dysregulation
When sugar or refined carbohydrate is consumed (particularly in isolation i.e. without fat or protein), it is rapidly digested and absorbed. This causes blood sugar to rise to high levels quickly which stimulates the release of large quantities of insulin. Insulin draws sugar into the cells to be stored as glycogen leading to a subsequent drop in blood sugar. This drop can cause sugar cravings, low energy, poor concentration and tiredness, which often leads to further consumption of sugar or refined carbohydrates and the cycle begins again – a blood sugar roller-coaster.
Eventually, this pattern can trigger insulin resistance, where the cells become fatigued from constant high insulin signalling and therefore no longer respond adequately to its release. This leads to the conversion of sugar into triglycerides to be stored as adipose (fat) tissue and therefore an increase in adiposity and also the progression towards type 2 diabetes where the cells no longer respond to insulin at all(10.)
Eating foods that are digested and absorbed slowly, i.e. low-glycaemic index foods, will result in a more sustained release of sugar into the blood, therefore lower levels of insulin will be needed, and the blood sugar highs and lows are avoided.
Sugar and the stress response
Sugar intake can increase levels of stress hormones such as cortisol which can in turn increase anxiety and lead to poor sleep among other things. Low blood sugar, or hypoglycaemia, that occurs due to poor blood sugar regulation stimulates the release of cortisol from the adrenal glands, this becomes a vicious cycle as increased cortisol can contribute to sugar cravings as well as central weight gain and hypoglycaemia.
Stress itself can also contribute to poor blood sugar regulation. When the body is under stress the adrenal glands release adrenaline as well as cortisol. These hormones trigger the release of sugar stored as glycogen into the bloodstream leading to high blood sugar levels and therefore an insulin response. There is, therefore, a vicious cycle of stress and sugar intake with one exacerbating the other.
High levels of cortisol are associated with increased anxiety, weight gain, low mood and poor sleep all of which are factors affecting the younger generation currently.(4,5)
Sugar and energy
It is true that sugar will give an almost immediate hit of energy, however, this is sometimes referred to as a “false energy” as it is short-lived. The dysregulation of blood sugar control, as mentioned above, leads to hypoglycaemia which makes us feel tired, lethargic and devoid of energy shortly afterwards. In addition excess sugar, particularly when coupled with insulin resistance, increases oxidative stress. Excess levels of oxidation can damage mitochondria, the organelles inside cells which are responsible for energy production. Damage to mitochondria has a detrimental effect on energy production and therefore exacerbates tiredness.(6)
Sugar and mood
It may seem, when you are feeling a bit down and reach for the chocolate, that sugar can improve mood. This is because it stimulates the release of neurotransmitters such as endorphins (feel good) and dopamine (reward-related), these make us feel good in the short term but subsequently, when the “hit” has worn off we are left unsatisfied and craving more. Studies have shown that low levels of the neurotransmitter serotonin, which are associated with depression and low mood, stimulate sugar cravings and hyperphagia (overeating). In turn, this affects the stress response and can eventually further impact mood, another vicious cycle!
The NHS states that almost one in four young people will experience depression before they are 19 years old(7.)
The other issue in relation to cognitive function is that the gut and the brain have a very strong connection via the vagus nerve which again relies heavily on the microbiome(8.) If this is dysregulated cognitive health can be impaired. When the gut is under stress it can become damaged and leaky, this means that larger molecules can pass through the digestive lining and enter the bloodstream, which triggers an inflammatory reaction. A leaky gut is likely to be associated with a leaky blood-brain barrier allowing passage of molecules which trigger inflammation or neuroinflammation. Neuro-inflammation is associated with low mood and depression(9.)
More people than ever, particularly children, may be suffering from ‘Hidden Hunger’. This is when people are eating sufficient calories (often ‘empty calories’) but not getting sufficient micronutrients (such as vitamins, minerals, flavonoids and essential fats) for optimal health leading to a ‘Nutrition Gap’ or ‘Hidden Hunger’. People are therefore overfed and undernourished.
Nutrients are essential for all functions of the body and deficiencies or sub-optimal levels of these nutrients can have a detrimental effect on all aspects of health discussed above. For example:
- Magnesium, vitamins C, B5 and B6 are all essential for a normal stress response
- Magnesium, zinc and chromium are involved in insulin signalling and therefore blood sugar regulation
- Vitamin B6 and magnesium are essential for serotonin production and therefore have an effect on mood etc
Therefore as well as reducing children’s daily sugar intake, it is also important to ensure a nutrient dense diet.(10)
Human beings are programmed to enjoy sugar. However, from an evolutionary perspective, we were not often exposed to it. When sugar was available, for example in the late summer/autumn when sweet fruits were ripening or when a bees’ nest full of honey was discovered, we would gorge on it to build up fat to allow us to survive the frugal winter months. We no longer live in a state of feast and famine and sugar is available to us all of the time. However, the craving for sugar still exists and the release of neurotransmitters following consumption has got us hooked!
It is all very well being told to reduce sugar intake but there are many sources of sugar that are not obvious and therefore it can be a minefield for parents when considering their weekly shop and meal preparation. Many processed foods, ready meals and ‘free from’ products have added sugar to improve taste and to hide the excess salt used as a preservative. So foods do not have to taste sweet in order to contain sugar – most loaves of bread will have sugar added to them! To add insult to injury it is not always easy to identify on the packaging as sugar does not just have to be labelled as sugar it is also known as (this list is not exhaustive):
- Malt extract / maltose
- Corn Syrup / Rice syrup
- Rice extract
It is also worth noting that highly refined or processed carbohydrates such as pasta, white bread and white rice are digested and absorbed so quickly by the body that the effect of eating them is very similar to consuming sugar itself.
Common foods in children’s diets that contain high amounts of sugar or refined carbohydrates are:
- Breakfast cereals
- Soft drinks (including fruit juice)
- Cereal bars
- Fruit yoghurts
- White bread/pasta/rice
Wholefoods, on the other hand, contain very little refined sugar and carbohydrates, therefore increasing fresh fruit, vegetables, lean protein and healthy fat can automatically help reduce sugar intake as well as stabilising and regulating blood sugar.
General rules to reduce sugar and stabilise blood glucose levels
- Ensure children eat 3-4 portions of vegetables and 1-2 portions of fruit per day.
- Include healthy fats and protein with each meal
- Use wholegrain carbohydrates
- Have 3 meals and 2 small snacks to stop overconsumption and excess hunger
Useful sugar swaps/snacks and meal ideas:
- Include cucumber, carrot or pepper crudités with hummus as a snack
- Grate carrot, courgette and onion to add to soups, stews, curries or bolognese to increase vegetable intake
- Offer fruit with nuts/seeds or nut butters as a snack
- Homemade smoothies made with coconut milk as a base (avoid fruit juice), with fresh fruit and seeds. Small amounts of avocado work well and vegetables such as spinach and cucumber can be added. See our Smoothies booklet for some recipe ideas.
- Try lower sugar bars such as Bounce balls or 9 bars
- Swap white pasta for wholegrain or buckwheat pasta and white rice for brown rice
- Stay hydrated
- Swap soft drinks and squashes for water with fresh fruit in such as strawberries, kiwi, lemon or watermelon, can use sparkling water as a treat
- Swap breakfast cereals for whole oats, add cinnamon or nuts and seeds or berries
- Swap white or milk chocolate for dark 70% chocolate
- Avoid processed foods and ready meals.
- Use a multivitamin and mineral to help bridge the nutrition gap
- Consider supporting the microbiome with a live bacteria supplement and/or fermented foods such as kefir, kombucha and sauerkraut (if tolerated)
- Noble EE, Hsu TM, Jones RB, Fodor AA, Goran MI, Kanoski SE. Early-Life Sugar Consumption Affects the Rat Microbiome Independently of Obesity. The Journal of Nutrition. 2017;147(1):20-28. doi:10.3945/jn.116.238816.
- Sen T, Cawthon CR, Ihde BT, et al. Diet-driven microbiota dysbiosis is associated with vagal remodeling and obesity. Physiology & behavior. 2017;173:305-317. doi:10.1016/j.physbeh.2017.02.027.
- Koliada A, Syzenko G, Moseiko V, et al. Association between body mass index and Firmicutes/Bacteroidetesratio in an adult Ukrainian population. BMC Microbiology. 2017;17:120. doi:10.1186/s12866-017-1027-1.
- Gyllenhammer LE, Weigensberg MJ, Spruijt-Metz D, Allayee H, Goran MI, Davis JN. Modifying Influence of Dietary Sugar in the Relationship Between Cortisol and Visceral Adipose Tissue in Minority Youth. Obesity (Silver Spring, Md). 2014;22(2):474-481. doi:10.1002/oby.20594.
- Gonzalez-Franquesa A, Patti ME. Insulin Resistance and Mitochondrial Dysfunction. Adv Exp Med Biol. 2017;982:465-520.
- Browning KN, Verheijden S, Boeckxstaens GE. The vagus nerve in appetite regulation, mood and intestinal inflammation. Gastroenterology. 2017;152(4):730-744. doi:10.1053/j.gastro.2016.10.046.
- Park C, Brietzke E, Rosenblat JD, Musial N, Zuckerman H, Ragguett RM, Pan Z, Rong C, Fus D, McIntyre RS. Probiotics for the Treatment of Depressive Symptoms: An Anti-Inflammatory Mechanism? Brain Behav Immun. 2018 Jul 13. pii: S0889-1591(18)30304-0.
- Textbook of Functional medicine, 2008.
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