Dominique Glatt, student dietian, Queen Margaret Uiniversity.

 

“Picasso”, “Shelly”, “British Queen”, “Red Duke of York”, “Charlotte” and “Kondo”1; these are only a few examples of the 300+ varieties of the potato which are grown nowadays14. The potato (Solanum tuberosum) is a tuberous (the edible swollen part of an underground stem – what we think of when we hear the word “potato”) annual plant of the deadly nightshade family (Solanaceae), and was first domesticated and cultivated by the Incas on the hills of Peru and Bolivia some 1800 years ago2. They spread to Europe in the 16th century and became a staple part of the Irish and German diets by the 18th century1; the infamous Irish Potato Famine was caused by late blight, a fungal infection (Phytophthora infestans))3 which resulted in mass starvation and emigration due to 30-40% of the Irish population being dependent on potatoes4.

Today, potatoes are the fourth leading food crop worldwide3 and remain a proud staple in the modern British diet. These tubers are a brilliant source of energy (carbohydrates and protein), fibre, B vitamins (thiamin and niacin), potassium and vitamin C5. While the potato is considered a vegetable, when you’re planning your meals they count as a portion of starchy carbohydrate due to their energy content6. Alas, they do NOT count as one of your Five-A-Day along with yams, plantain and cassava7.

There is no specific recommended portion size for potatoes, instead, the recommendation is that each meal should consists of just over one third of a starch, so that 50% of your total daily energy derives from starchy carbohydrates8. This can include, but is not limited to potatoes; other starchy carbohydrate sources include wholegrain breads, wholemeal pasta and noodles, or high fibre cereals (ex. oats or bran flakes)6. A general rule of thumb: one portion of starchy carbohydrate is roughly the size of your fist11. Adults should have between 6-8 portions a day (5 portions for children)9,10. An adult serving of potatoes works out to be (roughly) two egg-sized potatoes13. The following table shows the macronutrient and major micronutrient content of one portion of potatoes and the corresponding adult, adolescent and child reference nutrient intake (RNI); which is the recommended amount of nutrients to meet 97.5% of the populations needs8.

Nutrient Daily RNI of nutrients Nutrients per portion of boiled new potato with skin
Adults Adolescents Children
(18 years +) (11-17 years) (2-10 years) 120g 30-90g
Energy and Macronutrients
Energy (kcals) 77 19-58
Carbohydrate (g) 50% of daily food energy 17.9 4.5-13.4
Fibre (NSP) (g)* 30 25 15-20 2.2 0.5-1.6
Protein (g)  0.75g of protein per kg bodyweight 14.5g (1-3y) 19.7g (4-6y) 28.3g (7-10y) 2.2 0.5-1.6
Fat (g) 0.1 0.03-0.09
Micronutrients
Niacin (mg) 17 (M)

14 (F)

15-18 (M)          12-14 (F) 8-12 0.84 0.21-0.63
Thiamin (mg) 1.0 (M)

0.8 (F)

0.9-1.1 (M)       0.7-0.8 (F) 0.5-0.7 0.16 0.04-0.12
Vitamin C (mg) 40 35-40 30 8 2.1-6.3
Potassium (mg) 3500 3100-3500 3100-1100 (1100-800¤) 452 113-339
   
1 portion of potatoes which counts as 1 portion of starchy carbohydrate 2 egg-sized boiled potatoes (120g) 1/2 – 1 ½ egg-sized potatoes (30-90g)
Recommended number of portions of starch food a day 6-8 5
*AOAC value (McCance and Widdowson’s); ¤ Reference Range for 2-3 years; § M=male, F=female. References: Nutritional content of Potatoes 5; Reference Nutrient Intake 8; Portions of Potatoes 11; Recommended portions of starchy foods 9, 10.

 

Carbohydrates and kcal (energy) are often given a “bad rep” for weight gain, however, this is not true and in-fact it is the added fats (ex. butter) and sugar (ex. sauces) which contribute to weight imbalance6. High fibre starchy foods such as potatoes (with their skins on) or wholegrain products added volume to your meals and can help you feel full longer which may help control cravings. Dietary fibre also helps maintain healthy bowels by adding bulk and increasing transit time; it has been associated with a lower risk of developing colon cancer, cardiovascular disease and type 2 diabetes16. If you are a fan of potato salad, GOOD NEWS! The action of cooking and cooling the potatoes increases the amount of resistance starch (indigestible fibre) in the potato and helps promote a healthier gut bacteria15. Use a lighter/olive oil-based mayonnaise or an olive oil vinaigrette to keep an eye on those added fats and sugars.

Both Niacin (vitamin B3) and Thiamin (vitamin B1) are required for effective digestion and metabolism (energy release from food) and are essential for a healthy functioning nervous system8.One adult portion of potatoes provides roughly 5% of your daily RNI of niacin and roughly 18% of your daily RNI of tiamin8; the health department advises that we should all be able to meet our niacin and thiamin requirements with a healthy balanced diet and that there is no need for supplementation17. Other good sources for niacin: fish, eggs, meat, milk and wheat flour; and for thiamin: fresh and dried fruit, peas, eggs, and wholegrain breads17.

Normally potatoes are not considered as a main source of vitamin C, however, due to our high potato consumptions in the UK we can get a decent amount from these tubers6. Vitamin C aides in the maintenance of healthy connective tissue (preventing scurvy), helps in wound healing and prevents free radical damage in our cells by acting as an antioxidant8. It also aids in the absorption of non-heam iron (plant sourced iron), so accompany your serving of potatoes with some lightly steamed spinach18. One adult portion of potatoes provides roughly 20% of your daily RNI8. Vitamin C is water-soluble and can’t be stored in your body so you’ll need vitamin C every day, however, with a healthy balanced diet this is easy to achieve (alternative sources: citrus fruits and juices (150ml of 100% fruit juice can count as 1 of your 5 A DAY7), red and green peppers, broccoli, brussels sprouts, and strawberries18).

Potassium is a mineral required for our nerves to send signals to and from our brains, allows our muscles to contract (ex. a healthy beating heart), and maintains cellular fluid homeostasis (body fluid balance)8,19. One adult serving of potatoes provides roughly 13% of our daily RNI for potassium8; the rest of our daily requirements can easily be met by a healthy balanced diet. Other good potassium sources are bananas, broccoli, nuts and seeds, pulses, and meats5,19.

Cooking potatoes is where things get fun; you can boil, mash, roast, fry, or puree them with stock and vegetables into a hearty soup. Try cold vichyssoise for a fancy twist (cold leek and potato soup). Potato flour can be used as an alternative to wheat/rye flours for those of us who have Coeliac disease as potatoes are naturally gluten free (just check for cross contamination)20. A favourite treat from up North are “tattie scones”, a flat bread-like pancake-scone made from mashed potatoes. If you’re looking to make your potatoes healthy: keep the skin on to boost your fibre and vitamin intake, be aware of what you are adding to the cooking process (frying in oil vs. boiling in water), or swap butter for a little olive oil or reduced fat sour cream when mixing into mash6. If you know someone who is having trouble keeping weight on, add some grated cheese to your mashed potatoes; this will give a little extra protein (to help prevent lean muscle loss), and calcium (for healthy bones)21.

 

References

  1. Royal Horticultural Society (2011). RHS Award of Garden Merit, Potatoes 2011. Available from: https://www.rhs.org.uk/plants/pdfs/agm-lists/agmpotatoes (Accessed: 19/03/2017).
  2. Encyclopaedia Britannica (2016). Potato. Available from: https://www.britannica.com/plant/potato (Accessed: 19/03/2017).
  3. Encyclopaedia Britannica (2016). Solanales. Available from: https://www.britannica.com/plant/Solanales#ref595971 (Accessed: 19/03/2017).
  4. O’Neill, Joseph R. (2009). The Irish Potato Famine.
  5. McCance, R.A., and Widdowson. E.M., 2015. McCance and Widdowson’s The composition of foods: 7th summary edition [electronic resource].
  6. NHS Choices (2015). Starchy foods and carbohydrates. Available from: http://www.nhs.uk/Livewell/Goodfood/Pages/starchy-foods.aspx (Accessed: 20/03/2017).
  7. NHS Choices (2015). 5 A DAY: what counts?. Available from: http://www.nhs.uk/Livewell/5ADAY/Pages/Whatcounts.aspx (Accessed: 20/03/2017).
  8. Department of Health (1991). Dietary Reference Values for Food and Energy and Nutrients for the United Kingdom. Report of the Panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy.
  9. British Nutrition Foundation (2014). Perfect Portions for Toddler Tums. Available from: https://www.nutrition.org.uk/attachments/article/734/BNF%20Toddler%20Eatwell%20Leaflet_OL.pdf (Accessed: 21/03/2017).
  10. BUPA (2016). Portion size. Available from: https://www.bupa.co.uk/health-information/Directory/P/portion-size (Accessed: 20/03/2017).
  11. British Dietetic Association (2016). Food Fact Sheet: Carbohydrates. Available from: https://www.bda.uk.com/foodfacts/Carbs.pdf (Accessed: 20/03/2017).
  12. British Dietetic Association (2016). Food Fact Sheet: Portion Sizes. Available from: https://www.bda.uk.com/foodfacts/portionsizesfoodfactsheet.pdf (Accessed: 20/03/2017).
  13. University Hospitals of Leicester NHS (2012). Carbohydrates: PORTION LIST. Available from: http://www.leicestershirediabetes.org.uk/uploads/123/documents/NewCarbohydratePortionList285.pdf (accessed: 19/03/2017).
  14. AHDB Potato Variety Database (2007-2017). Varieties. Available from: http://varieties.ahdb.org.uk/varieties (Accessed: 22/03/2017).
  15. British Nutrition Foundation (2016). Resistant Starch. Available from: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/resistant-starch.html (Accessed: 21/03/2017).
  16. Gandy, J., 2014. Manual of Dietetic Practice, 5th edition, Wiley-Blackwell.
  17. NHS Choices (2015). Vitamins and minerals – B vitamins and folic acid. Available from: http://www.nhs.uk/Conditions/vitamins-minerals/Pages/Vitamin-B.aspx#folic-acid (Accessed: 20/03/2017).
  18. NHS Choices (2015). Vitamins and minerals – Vitamin C. Available from: http://www.nhs.uk/Conditions/vitamins-minerals/Pages/Vitamin-C.aspx (Accessed: 20/03/2017).
  19. NHS Choices (2015). Vitamins and minerals – Other vitamins and minerals. Available from: http://www.nhs.uk/Conditions/vitamins-minerals/Pages/Other-vitamins-minerals.aspx#potassium (Accessed: 20/03/2017).
  20. Coeliac UK (2016). Gluten Free Checklist. Available from: file:///C:/Users/Daydreamer/Downloads/gluten-free-checklist-web.pdf (Accessed: 20/03/2017).
  21. British Dietetics Association (2016). Food Fact Sheet: Malnutrition. Available from: https://www.bda.uk.com/foodfacts/MalnutritionFactSheet.pdf (Accessed: 22/03/2017).