FREQUENTLY ASKED QUESTIONS

YOUR POTATO QUESTIONS Answered


Potatoes contain a variety of nutrients and are major contributors of important minerals to the diet such as potassium and chromium. Despite what some people think, potatoes (boiled with skin), are naturally free of fat, high in carbohydrates (complex carbohydrates) and naturally low in sodium.

Added elements such as oil, butter or cream create a higher fat content in potatoes. 1medium potato provides only 498kJ and approximately 24g of carbohydrates. That is the equivalent of one and a half carbohydrate servings. According to Professor Esté Vorster, Director: Africa Unit for Transdisciplinary Health Research at the Faculty of Health Sciences of North West University: “Potatoes, when boiled in their skin, have low energy values and are ideal for both slimming and maintaining a healthy body weight.”

One needs to remember that it is the fillings and cooking method that effective the kilojoule content of potatoes. Team your potato up with low fat, nutritious fillings. Sensible eating is not about restricting certain food groups from the diet. It is about achieving balance and listening to your body and adopting a longer-term healthy eating plan that will continually benefit you.


Potatoes, cooked with skin, provide a wide range of nutrients. They are high in carbohydrates and the mineral chromium. They also have one of the highest levels of potassium when compared to other vegetables and starchy foods.

Below is a list of the vitamins and minerals contained in 1medium potato.

Vitamins Per single 150g serving %NRV*
Vitamin B2 (mg) 0.1 5%
Niacin (mg)** 2.4 15%
Vitamin B6 (mg)** 0.5 29%
Vitamin C (mg) 8.2 8%
Pantothenic acid (mg)** 0.8 17%
Minerals
Copper (mg) 0.2 27%
Chromium (ug) 15 43%
Iron (mg) 1.8 10%
Magnesium (mg) 39.1 9%
Manganese (mg) 0.3 14%
Phosphorus (mg) 98.9 8%
Potassium (mg) 710 **
Zinc (mg) 1.5 13%

Information for cooked potato with skin

*Nutrient Reference values (NRV’s) for individuals 4 years and older expressed per single serving.
**NO NRV available


Potatoes have been unfairly criticized for their ranking on the GI. In fact there are a number of complexities in the measure and methodological weaknesses inherent in the determination of GI, which severely limits the simple classification of a given food as high, medium or low on the GI, as well as the application of the GI for the purpose of food selection (Franz 2006). First and foremost, it must be emphasized that the GI is not an inherent property of a food but, rather, the metabolic response of an individual to a food (Pi-Sunyer 2002). Thus, the GI of a carbohydrate-rich food can Vary greatly depending on a number of factors, including:

  • Processing/preparation.
  • Variety, origin, maturation.
  • Addition of other macronutrients (protein, fat, fiber).

Ways to decrease the GI of potatoes:

  • Combine potatoes with protein rich food such as low fat cottage cheese or tuna.
  • Allow potato to cool after cooking.

In 2011, Potatoes South Africa conducted a hydrolysis index test. This screens the GI of foods. Hydrolysis index (HI) values predict that floury potatoes, such as the Darius cultivar, could possibly have an intermediate GI, while waxy potatoes such as the Mondial cultivar are predicted to have a high GI, as generally accepted for potatoes by the Glycaemic Index Foundation of South Africa (GIFSA).

“This provides evidence to suggest that, different cultivars with different dry matter and starch contents, as well as those grown in different regions and under different growth conditions could have different GI values.” Nicolette Gibson, Faculty of Natural and Agricultural Sciences, University of Pretoria.

In conclusion:

Like the low-carbohydrate craze that preceded it, the GI has enjoyed increasing popularity despite the lack of research to support its efficacy as a dietary tool for weight loss, disease prevention, and/or health promotion. However, unlike the low-carbohydrate diets whose popularity could be attributed in a large part to their simplicity (i.e., just eliminate carbohydrates from the diet), the GI is considered rather complex and this is made even more complex by the multitude of factors that can impact it (e.g., processing, preparation, maturation, the addition of other macronutrients, time of day, etc.). Until large-scale studies are done using the GI in a variety of circumstances and disease conditions, South Africans should strive to follow the food based dietary guidelines.


While high-protein, low-carbohydrate eating plans may show some external physical results, it is not necessarily doing us any favours in the long term. Low carbohydrate diets can result in fatigue and dehydration caused by increased protein metabolism, which also places strain on our kidneys. By restricting our intake of carbohydrates we also starve the body of the dietary fibre that is important for healthy digestion. The starch in potatoes yields glucose that is essential for our mental and physical energy, so yes, you really do need carbohydrates in your diet and potatoes are an ideal source.

Your body needs a variety of foods in a balanced diet. But use a little nutrition sense when selecting starches. Chose starchy foods that contain dietary fibre, are close to their natural form (not overly processed), and are high in key nutrients.


Potatoes should be stored in a dark, dry and cool place that is well-ventilated. Keep them separate from pungent vegetables (which give off gasses that promote decay in potatoes). Take them out of plastic bags.


The green colour sometimes found in potatoes is caused by chlorophyll and indicates that solanine is present. It is usually due to the potato’s exposure to light. Solanine is a natural toxin that is only really harmful in large doses. Nevertheless, if a potato is green in parts, simply cut off the green bit and prepare the remaining potato as usual.


Sprouting potatoes are typically not fresh but can be eaten if you break off the sprouts.


Many people may be confused about the difference between a “starch” and a “carb” or “carbohydrate”. We often use these terms interchangeably and many people are said to be “cutting carbs” or “avoiding starch” to improve health or lose weight. Let’s clear up the confusion once and for all and understand better, what these jargon terms really mean.

Carbohydrates: The Food Group

All food is grouped according to three main groups or macronutrients: Carbohydrates, Fats or Proteins. Within the carbohydrate group, foods are further divided into 4 sub-categories. These are: starches; sugars; fruits and vegetables. Yes, you read correctly: vegetables are also carbohydrates! Each carbohydrate sub-group contributes its own unique nutrients or attributes to the diet.

Starches

The starch includes foods such as rice, bread, cereals, potatoes, crackers, pasta, quinoa, cous-cous and a variety of other grains. These foods are a great source of energy in the diet and high-quality options that are higher in fibre with a variety of B-vitamins. In order to get the benefits from starches, be sure to choose whole food options. Always remember that, the preparation does matter. Take care when preparing starches to limit fat or oil.

In the case of potatoes, always leave the skin on. Potatoes; baked, boiled or steamed provide optimal nutrient levels. Check packaging information on starches and aim to select starch options that have a higher fibre content. The aim is to choose starches with fibre higher than 6g per 100g.

Sugars

This sub-group of carbohydrates has taken a bad rap of late! A big reason for this is that sugars are becoming more and more prevalent in the diet and are regularly being added to foods and used in excessive amounts. There is no denying it, sugar is tasty and has a very high palatability. It can also be used as a preservative to increase the shelf life of foods such as pickles or jams. According to the World Health Organization, consumption of sugar should be no more than 5-10 teaspoons per day. Without realizing it, these teaspoons rack up quickly as added sugars are found in sauces, condiments, fruit juices, smoothies and many other packaged and processed foods. Sugar or honey (also a type of sugar) are also often added to hot beverages such as tea and coffee, and can contribute significantly to daily sugar intakes. Other sugars to be aware of are those more obvious ones found in chocolates, sweets, biscuits, cakes and other baked goods that are becoming increasingly consumed in the Westernized diet. It is vital to assess the diet for sugar content and avoid high intakes of sugars which contribute to high amounts of energy but very little nutrients to the diet. These energy-dense, high-sugar foods can increase total caloric intake and contribute to weight gain and other health complications such Diabetes and Heart Disease.

Fruits

Fruit too, is classified as a carbohydrate. Fruit is rich in natural sugars which are mainly in the form of fructose. Fructose is metabolised through different pathways in the body compared to the sugars mentioned above (sucrose) and because of this, the natural sugars found in fruit are released more slowly into the blood. This contributes to more stable energy release and blood sugar control throughout the day. Fruit, in its whole form, is also a source of fibre and this fibre is beneficial for gut health and also contributes to the slower release of fructose into the blood. Choose fruit in the natural, fresh form to get the most benefits which include fibre, vitamins, minerals and phytochemicals. Fruit juices, some smoothies, dried fruit and other fruit syrups are altered from their natural state and as such must be portion controlled if they are included in the diet. Many of them have sugars added or have had their fibre removed which decreases their benefits in the diet and impacts how quickly the sugars become available in the blood stream which can impact blood glucose levels.

Vegetables

The hero of the carbohydrate group, vegetables are a rich source of vitamins, minerals and phytochemicals and are also a source of fibre in the diet. There really is no negative when consuming any vegetables, they should be eaten in abundance in the diet. Particularly colourful vegetables as the different colours indicate that a variety of phytochemicals are available in the diet. So eat the colour of the rainbow on your plate every day and up-size portions of vegetables to improve satiety and fullness from meals which can assist with weight maintenance and even weight loss. Aim to eat 3-4 cups of vegetables every day, this will significantly improve your overall health.

What’s in a name?

And there you have it – clarity amidst the confusion! As you can see, there is no need for “name calling” when it comes to the different food groups. Better understanding and knowledge of where all foods fit in and the role they play in the diet, is far more beneficial in helping us to choose the best choice carbs, so that we can reduce risk of chronic disease and live a healthier life all-round.

Refrences

  1. Mahan, L. K., & Raymond, J. L. (2016). Krause's food & the nutrition care process. Elsevier Health Sciences.
  2. GBD 2017 Diet Collaborators. (2019). Health effects of dietary risks in 195 countries, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017. The Lancet [Published Online: April 3, 2019 http://dx.doi.org/10.1016/S0140-6736(19)30041-8].
  3. Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E., & Te Morenga, L. (2019). Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet, 393(10170), 434-445.