Deficiency Series- Are Our Teenagers Healthy?

Deficiency Series- Are Our Teenagers Healthy?

The stereotype of being a ‘moody defiant teenager’ certainly extends itself to encouraging a healthy diet in teenagers. Junk food, sugar sweetened drinks and snack food describes the typical composition of a UK teenager's diet aged 13 to 19 years. With such little focus on their diet, what harm is it doing to their health in the long term?

What is the diet of an average teenager like?

The years deemed as the ‘teenage years’ (13-19) are one of the most vital for the growth and lifelong health. This encompasses the average ages that of puberty. Puberty is the period of an adolescents life cycle in which they become young adults and their body begins to change. To do so they need adequate nutrition. Studies have shown children who have had any kind of malnourishment are less developed, and have a slower growth progression [1].

In as little as 10 years our rates of adolescent obesity have increased drastically. A 2014/15 statistic showed over 1/5th of teenagers were obese and an even greater fraction were overweight. This has resulted from poor nutrition and sedentary lifestyles.

The average diet of a teenager is rich in saturated fats, sugar and sodium, yet low in fish, wholegrains, vegetables, fruits and the vitamins and minerals that they are abundant in. The National Diet and Nutrition Survey (NDNS) revealed that out of a daily 400g target for fruit and vegetable consumption, 15-18 year olds consumed just 200g/day. Additionally, fibre intakes were as abysmal. The 2015 target for fibre is 24g of fibre, the NDNS found an intake of just 13.3g for boys and 10.6g for girls. The risk of this, of course is poor bowel movement which increases the chance of bowel cancer in later life. Moreover, we have seen a decrease in the intake of Calcium rich dairy foods, due to ‘health reasons’ and an increase in Veganism. This has sparked concern for the wellbeing of our adolescents bones and teeth, especially as sugar sweetened drink intake is at an all time high. Also, red meats have gone out of favour, due to health scares that excessive amounts of it may cause cancer. That being said the majority of red meat consumed by teenagers is in processed foods such as burgers. One mineral red meat is abundant in is Iron, a prominent cause for concern in the health of our adolescents [3,4,5].

What deficiencies are typical in teenagers?

Their greatest intake of non-extrinsic milk sugars (glucose,fructose) come from sugar-sweetened drinks (37%) such as cola. Not only is this detrimental to our waistbands but our dental and bone health too. Fizzy Drinks contain phosphoric acid and citric acid which strips the structural minerals from the bone, which lowers bone density and leaves them brittle. Continuation of this over many years can lead to osteoporosis [6]. Another concern for bone and dental health is the lack of Vitamin D and Calcium in the Adolescent population. Typical intakes of Calcium are between 800mg-1000mg dependent on gender, however, it’s believed that between 9-13% of boys and 19-24% of girls are deficient. Considering that 50% of the adult skeleton is developed in the teenage years it is essential to consume the recommended daily amounts of Calcium. The poor bone structure created as an adolescent can lead to osteoporosis, arthritis and low bone density as an adult. For Calcium to be efficiently absorbed into the bone it requires Vitamin D, however, a 2016 study on Vitamin D has shown that UK adolescents do not meet adequate vitamin D intakes. Yet they found that supplementation of between 10ug and 30ug a day was enough to maintain the required Vitamin D concentrations and avoid deficiency that may lead to age-related bone loss in later years[5].

Iron during the teenage years, particularly in girls is vital. Adolescence marks the start of puberty and menstruation in girls. Hence, why Iron recommendations increase to 14.8mg per day. For boys of the equivalent age, Iron intake is also greater at 11.3mg, because it is required for growth. The most concerning area of deficiency is in girls between 44-48%, whereas only 3% are deficient in Iron [5]. Iron is found in cocoa and dark leafy green vegetables and red meat, but Iron can easily be lost in over-processing, such as when making burger patties. Additionally, Iron is sensitive to anti-nutrients. Anti-nutrients are foods or nutrients that inhibit absorption of Iron. To enhance Iron absorption, Iron-rich foods should be consumed with dietary sources of Vitamin C or meat products [8].

Fruit and Vegetable intake is poor within Britain within the whole of the nation, but particularly in adolescents. One statistic suggested that only 21% of adolescents consumed their 5-a-day [9]. In particular, fruits and vegetables are rich in Vitamin C . Vitamin C is a water-soluble vitamin found abundantly in kale, spinach, strawberries and mango, however it is also found in more common vegetables such as potatoes and carrots too. The benefit of vegetables is they are low calorie, full of water and fibre. However , Vitamin C is essential for energy production, immune system and nervous system function. Also, as previously mentioned Vitamin C will help to increase Iron absorption too, thus improving two areas of health. Fruits and vegetables are also rich in Potassium which is good for maintaining healthy blood pressure. Current dietary habits are setting our children up for poor health in the future particularly associated with Hypertension. Teenage diets are rich in fast-option processed snacks rich in sodium salts. A counteracting supplement to the effect of Sodium is Potassium. Potassium found in fruits and vegetables such as avocados, spinach, bananas and kiwis. Potassium has been found to reduce blood pressure by as much as 3-6mm/Hg.

What can be done to improve this?

  • Reduce saturated fat, increase poly- and monounsaturated fats in the diet. Foods rich in these include fish, seeds, nuts, plant oils and avocados.
  • Increase dietary Iron sources or choose an Iron Supplement providing 14mg+ per day.
  • Increase potassium intakes and actively attempt to reduce sodium intakes.
  • Cut out all sugar-laden fizzy drinks.
  • Eat 5 or more fruits and vegetables a day.
  • Take care of your bone density by including more Vitamin D and Calcium in your diet.
  • Increase your fibre intake by eating more unskinned vegetables and fruit, and always opt for brown or wholegrain varieties.
  1. Walker.SP, Golden.MH. (1988). Growth in length of Children Recovering from Severe Malnutrition . European Journal of Clinical Nutrition . 42 (5), Pg. 395-404.
  2. PHN. (2016). UK prevalence. Available:
  3. NHS. (2011). Children's diets 'still lack nutrition'. Available:
  4. Henderson L, Gregory J, Irving K, et al. (2003a) The National Diet and Nutrition Survey: adults aged 19-64 years. Volume 2. Energy, protein, carbohydrate, fat and alcohol intake. HMSO: London, UK.
  5. Henderson L, Irving K, Gregory J et al. (2003b) That National Diet and Nutrition Survey: adults aged 19-64 years. Volume 3. Vitamin and mineral intake and urinary analysis. HMSO: London, UK.
  6. Tucker. KL, et-al. (2006). Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study.. The American Journal of clinical nutrition . 84 (4), Pg.936-942.
  7. Smith.T- et-al. (2016). Study reveals high levels of vitamin D inadequacy in UK adolescents. Available:
  8. BNF. (2015). Teenagers. Available:
  10. .Mann.J, Chisholm.A. (2012). 21: Cardiovascular disease. In: Mann,J. Truswell,S. Essentials of Human Nutrition. 4th ed. Oxford: Oxford University Press. Pg. 326-358.
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