Although popular, potatoes have been the subject of much unfair criticism regarding their role in weight loss, low GI and low carbohydrate diets. However, it is evident from their 'stand-out' nutritional qualities that they fit well into a balanced diet.
The facts are:
'A high intake of fruit and vegetables reduces the risk of
coronary heart disease'
This is a recognised high level health claim and guess what? The potato is a vegetable.
'Fruit and vegetables automatically qualify for the Heart Foundation Tick'
This is a trusted, independent, not-for profit program and guess what? The potato is a vegetable.
Children all over the world eat the versatile potato with little complaint, but in the adult developed world, many consumers have discarded potatoes from their diets because they believe that potatoes are fattening, high in “bad carbs” and full of “empty” calories. There is also a lot of discussion about foods which are high or low GI.
But what does this really mean or measure?
Glycemic Index (GI)
The GI is proposed as tool to rank foods based on their immediate effect on blood sugar levels and to evaluate low-GI foods based on the speed at which they enter the bloodstream.
The GI ratings are:
- High GI > 70
- Medium GI 56-69
- Low GI < 55
The potato has a GI of 65-101 and is generally considered to be a high GI food although this is dependent on variety and cooking method. Not all potatoes fall into this category and some potato varieties have actually been tested and given a “low” glycemic index. There is large variability and it is influenced by methodology.
However, the index has some limitations in its use. The index does not reflect the glycemic variation in potatoes due to factors such as variety, country of origin, processing or preparation techniques. It is known that the GI of cooled potatoes is significantly lower compared with potatoes consumed immediately after cooking. Cold storage can also reduce GI values.
The GI does not reflect the nutrient content of food. Many nutrient poor, high energy foods such as chocolate have a low GI, and so the overall health benefits of a food cannot be based on this index alone.
In addition, eating potato with other foods, often lowers the overall GI value substantially.
Potatoes also get a bad 'rap' because of the heavy foods associated with them including butter, margarine, sour cream, cheese, bacon and fatty oils. For this reason, potatoes have been blamed for weight gain. However, when cooked simply in their skins, the potato is a vitamin tablet, a nutritious way of receiving your dietary fibre and carbohydrate requirements and a healthy choice in any diet. In fact, the potato is a nutrient-dense food which means that for the amount of calories it contains, it provides a good nutritional return.
Potatoes boiled with their skin on are actually naturally free of fat. However, the choice of cooking method affects overall fat content.
This table illustrates these variations per 100g of potato:
|Cooking method||Fat content (grams)|
|Baked Jacket Potato||0.3|
|Fat Chips (Fish & Chip Shop)||9|
|Peeled & Roasted||5|
Here are the statistics and facts about the nutrients and health benefits of fabulous potatoes:
- 99.9% fat free
- Gluten free
- Less calories than rice and pasta
- Cholesterol free
- Very low in salt (sodium)
- More fibre than five bananas
- More potassium than a banana
- Twice the Vitamin C of blueberries, more Vitamin C than an orange
Recommended daily intake
|Quantity per serving||% Daily Intake (per serving)||Quantity per 100g (or 100ml)|
|Energy||421.5 kj (100.8 cal)||5%||281 kj (67 cal)|
|Protein||3.57 g||8%||2.5 g|
|Fat, total||0 g||0%||0 g|
|- saturated||0 g||0%||0 g|
|Carbohydrate||19.2 g||6%||12.4 g|
|- sugars||0.6 g||1%||0.4 g|
|Sodium||4.5 mg||0%||3 mg|
|Vitamin C||31.5 mg||70%||21 mg|
|Fibre||3.45 g||12%||2.3 g|
Cooking method was boiled with skin on as this is the preferred preparation method. Percentage daily intakes are based on an average (8700kj) may be higher or lower depending on your energy levels. Percentage Recommended Dietary Intakes (RDI) were calculated using the schedule Standard 1.1.1 of the FSC.
|Nutrient||Potato, non specified type, boiled, no added salt/fat (100g)|
|Vitamin C (mg)||21|
|Niacin (mg niacin equiv.)||1.4|
|Vitamin B-6 (mg)||0.1|
|Total folate (µg)||11|
*Potato Nutrient values used for comparisons are from the Australian AusNut database.
The significant nutrients are :
- Vitamin C - 45%
- Potassium - 18%
- Vitamin B6 - 10%
For further information, download the full Potato Nutrition Report.
How are these significant nutrients used by the body?
Potatoes are an excellent source of vitamin C, with one potato providing 45% (27 mg) of your daily recommendation. This water-soluble vitamin acts as an antioxidant and can stabilise free radicals to help prevent damage to cells, including prevention of some cancers.
Vitamin C is also necessary for normal structure and function of connective tissue, including collagen production, a process that helps maintain healthy gums, skin, healing processes, bones and cartilage. Vitamin C boosts iron absorption and may help support the body's immune system.
It also reduces the risk of heart disease by preventing cholesterol from oxidizing in the bloodstream.
Potatoes are among the top sources of potassium. In fact, potatoes have more potassium per serving than any other vegetable or fruit, including bananas, spinach, broccoli, oranges, or mushrooms. Research suggests that diets rich in potassium and low in sodium may reduce the risk of hypertension and stroke and help lower blood pressure. The low sodium content of potatoes (0.15 mg per 100g) also assists in the lowering of the incidence of the development of cardiovascular disease.
Potassium aids in the control of water uptake and helps maintain the optimal acid-alkali balance (pH) in the body.
Potatoes are a good source of vitamin B6, a water soluble vitamin that plays important roles in carbohydrate and protein metabolism.
There is more iron in a potato than half a cup of spinach.
It helps the body make amino acids, used by the body to manufacture various proteins, assists with the health of the nervous system and reduces levels of homocysteine, a chemical that can contribute to atherosclerosis and other cardiovascular diseases.
If Popeye the Sailorman had known this, he may well have swapped his can of spinach for a baked potato!
Carbohydrates are a major source of energy for the body. There are two types: simple and complex. Simple carbohydrates include sugars found naturally in fruits, but not so naturally in dairy products and sweet treats.Simple carbohydrates are quickly broken down and absorbed by the body for a quick burst of energy. Complex carbohydrates come from starches such as breads, cereals, pasta, beans and potatoes. These carbohydrates provide a more gradual energy release and generally more nutritional value than simple carbohydrates.
Dieticians and nutritional experts state that 50-60% of our daily energy intake should come from carbohydrates, and one of the best sources is the potato. In fact, the body prefers to burn carbohydrates. There is no doubt that athletes who fuel up on only noodles and pasta are overlooking a carbohydrate source that's better; and that’s the potato which provides higher amounts of vitamin C, potassium, vitamin B6 and folate (vitamin B9).
Baked, mashed, or boiled, potatoes actually provide more energy-delivering complex carbohydrates than a cup of pasta.
One medium potato with the skin provides 8% of the daily recommendation. Dietary fibre, a complex carbohydrate, is the part of the plant that cannot be fully digested and absorbed into the bloodstream. It has been shown to have numerous health benefits, including improving the lowering the risk of gastrointestinal diseases, diabetes, and obesity, and increasing feelings of fullness or satiety, which may help with weight management.
Folate is necessary for normal blood formation and the prevention of neural tube defects in unborn babies.
Currently, R&D programs have led to the production of specific potato varieties which contain higher than typical amounts of certain nutrients.
Nutritional value of potatoes, pasta and rice
There is no doubt that rice and pasta have eroded the potato's market share over the past two decades due to the considerable development of our cultural diversity.
This table demonstrates that potatoes have significantly higher levels of fibre, potassium and vitamin C than both pasta and rice, and have significantly lower levels of carbohydrate and fat. These benefits are additional to the potato's great taste and texture.
Additionally, substituting the carbohydrate portion of a main meal from rice or pasta to an equivalent serve of potato will actually decrease the overall energy content of the meal. Potatoes are also more satiating than rice or pasta, so smaller amounts are typically consumed, and there is a further decrease in total energy intake.
|Vitamin C (mg)||28||0||0|
Europatat Congress 2007 – Prof. John Van Camp / Faculty Bio-Science Engineering – Department Food Safety and Food Quality, Ghent University, Belgium
Coloured potatoes: Do they have more nutrients?
There are thousands of potato varieties, each of them with unique nutritional properties. Generally, you will be able to tell if a particular variety is higher in a certain nutritional property than another by its colour. Here is how colour translates to nutrition:
Blue or Purple skin and/or flesh are an indication that this variety will have higher anthocyanins than other potatoes. Anthocyanins belong to a nutritional group called flavonoids which are powerful antioxidants, helping to reduce the risk of heart disease, diabetes and certain types of cancer. There is also evidence to support that these purple pigments assist in maintaining brain function with ageing. American scientists have found that a couple of servings of blue or purple potatoes a day also reduces blood pressure almost as much as oatmeal. The average diastolic pressure dropped by 4.3% and the systolic pressure decreased by 3.5% over the trial period.
Red skin is associated with the presence of Lycopene, the most powerful carotenoid which is a class of antioxidant.
White skin and/or flesh is associated with Allicin, an organic compound which exhibits antibacterial and anti-fungal properties. Allicin has the ability to dissolve fats but t is slowly destroyed by storage and quickly destroyed by high heat cooking.
Yellow or Orange flesh is associated with Beta Carotene, a class of molecules in the carotene group, also known as Vitamin A.
Potatoes can aid in the prevention of disease
Cardiovascular Disease (CVD) is the term used to describe heart, stroke and blood vessel disease. CVD is the leading cause of death in Australia. Dietary factors that are linked to the development of CVD include:
- Increased intake of saturated and trans fatty acids
- Increased intake of sodium
- Low intake of fibre
- Increased weight
Potatoes possess many properties that have been shown to have an inverse relationship with the development of cardiovascular disease. Potatoes are naturally very low in fat including saturated fat (99.9% fat free), contain almost no sodium (0.15mg per 100g) and are high in fibre.
The incidence of Type 2 Diabetes in young adults is increasing. Managing diabetes focuses on modifying carbohydrate intake to a level at which the individual’s insulin producing capacity can effectively deal with the glucose consumed. Consuming potatoes has not been shown to increase this risk; in fact, the high fibre of potatoes reduces the risk by slowing glucose absorption from the small intestine into the blood.
This disease is characterised by a permanent intestinal intolerance to gluten. This means that sufferers need to avoid pasta and bread. Potatoes are a naturally gluten-free source of carbohydrates suitable for individuals with coeliac disease.
Diets low in fibre contribute to constipation, haemorrhoids, diverticulitis, irritable bowel syndrome and colon cancer. Foods that are a good source of fibre, such as potatoes, play an important role in preventing and managing these conditions. In addition to the insoluble fibre content of potatoes, resistant starch is an important component of the fibre content of potato.
Resistant starch is found in cooked, cooled potatoes. It is important for maintaining good bowel health. Microbial fermentation of resistant starch in the large bowel forms short-chain fatty acids (butyrate, acetate and propionate), which are important to bowel health. These fatty acids are also absorbed into the bloodstream and may play a role in lowering blood cholesterol levels.
The rates of overweight and obesity amongst adults have doubled over the past two decades with Australia now ranked as one of the fattest developed nations. Most recent estimates suggest more than 60% of the adult population is overweight or obese. Of even greater concern is that 20-25% of Australian children are either overweight or obese, and trends suggest that these figures, much like the figures for adults, are gradually increasing.
BUT Potatoes do not possess any intrinsic properties which will cause weight gain in a well-balanced diet.
Satiety refers to the physiological and psychological experience of fullness that comes after eating or drinking. Potatoes have a very high Satiety Index (SI), more than three times that of white bread.
Next time your body is asking for a healthy fuel, choose the potato!
Fresh Potatoes. A report on the nutritional qualities of potatoes and summary of the role potatoes play in the Australian diet, Clued on Food, Accredited Practicing Dietitians 2008.
For further information download the Australian Government's Eat for Health Australian dietary guidelines summary