Whether mashed, baked or roasted, people often consider potatoes as comfort food. It is an important food staple and the number one vegetable crop in the world. Potatoes are available year-round as they are harvested somewhere every month of the year.
The potato belongs to the Solanaceae or nightshade family whose other members include tomatoes, eggplants, peppers, and tomatillos. They are the swollen portion of the underground stem which is called a tuber and is designed to provide food for the green leafy portion of the plant. If allowed to flower and fruit, the potato plant will bear an inedible fruit resembling a tomato.
Potatoes are a very popular food source. Unfortunately, most people eat potatoes in the form of greasy French fries or potato chips, and even baked potatoes are typically loaded down with fats such as butter, sour cream, melted cheese and bacon bits. Such treatment can make even baked potatoes a potential contributor to a heart attack. But take away the extra fat and deep frying, and a baked potato is an exceptionally healthful low calorie, high fiber food that offers significant protection against cardiovascular disease and cancer.
Our food ranking system qualified potatoes as a very good source of vitamin B6 and a good source of potassium, copper, vitamin C, manganese, phosphorus, niacin, dietary fiber, and pantothenic acid.
Potatoes also contain a variety of phytonutrients that have antioxidant activity. Among these important health-promoting compounds are carotenoids, flavonoids, and caffeic acid, as well as unique tuber storage proteins, such as patatin, which exhibit activity against free radicals.
Blood-Pressure Lowering Potential of Potatoes
UK scientists at the Institute for Food Research have identified blood pressure-lowering compounds called kukoamines in potatoes. Previously only found in Lycium chinense, an exotic herbal plant whose bark is used to make an infusion in Chinese herbal medicine, kukoamines were found in potatoes using a new type of research called metabolomics.
Until now, when analyzing a plant’s composition, scientists had to know what they were seeking and could typically look for 30 or so known compounds. Now, metabolomic techniques enable researchers to find the unexpected by analyzing the 100s or even 1000s of small molecules produced by an organism.
“Potatoes have been cultivated for thousands of years, and we thought traditional crops were pretty well understood,” said IFR food scientist Dr Fred Mellon, “but this surprise finding shows that even the most familiar of foods might conceal a hoard of health-promoting chemicals.” Another good reason to center your diet around the World’s Healthiest Foods!
In addition to potatoes, researchers looked at tomatoes since they belong to the same plant family—Solanaceae—as Lycium chinense. Metabolomic assays also detected kukoamine compounds in tomatoes.
The IFR scientists found higher levels of kukoamines and related compounds than some of the other compounds in potatoes that have a long history of scientific investigation. However, because they were previously only noted in Lycium chinense, kukoamines have been little studied. Researchers are now determining their stability during cooking and dose response (how much of these compounds are needed to impact health).
Vitamin B6—Building Your Cells
If only for its high concentration of vitamin B6—1 medium potato contains over one-half of a milligram of this important nutrient—the potato earns high marks as a health-promoting food.
Vitamin B6 is involved in more than 100 enzymatic reactions. Enzymes are proteins that help chemical reactions take place, so vitamin B6 is active virtually everywhere in the body. Many of the building blocks of protein, amino acids, require B6 for their synthesis, as do the nucleic acids used in the creation of our DNA. Because amino and nucleic acids are such critical parts of new cell formation, vitamin B6 is essential for the formation of virtually all new cells in the body. Heme (the protein center of our red blood cells) and phospholipids (cell membrane components that enable messaging between cells) also depend on vitamin B6 for their creation.
Potatoes are Rich in Vitamin B6—Brain Cell and Nervous System Activity
Vitamin B6 plays numerous roles in our nervous system, many of which involve neurological (brain cell) activity. B6 is necessary for the creation of amines, a type of messaging molecule or neurotransmitter that the nervous system relies on to transmit messages from one nerve to the next. Some of the amine-derived neurotransmitters that require vitamin B6 for their production are serotonin, a lack of which is linked to depression; melatonin, the hormone needed for a good night’s sleep; epinephrine and norepinephrine, hormones that help us respond to stress; and GABA, which is needed for normal brain function.
Potatoes are Rich in Vitamin B6—Cardiovascular Protection
Vitamin B6 plays another critically important role in methylation, a chemical process in which methyl groups are transferred from one molecule to another. Many essential chemical events in the body are made possible by methylation, for example, genes can be switched on and turned off in this way. This is particularly important in cancer prevention since one of the genes that can be switched on and off is the tumor suppressor gene, p53. Another way that methylation helps prevent cancer is by attaching methyl groups to toxic substances to make them less toxic and encourage their elimination from the body.
Methylation is also important to cardiovascular health. Methylation changes a potentially dangerous molecule called homocysteine into other, benign substances. Since homocysteine can directly damage blood vessel walls greatly increasing the progression of atherosclerosis, high homocysteine levels are associated with a significantly increased risk for heart attack and stroke. Eating foods rich in vitamin B6 can help keep homocysteine levels low. In addition, diets high in vitamin B6-rich foods are associated with overall lower rates of heart disease, even when homocysteine levels are normal, most likely because of all the other beneficial activities of this energetic B vitamin.
A single baked potato will also provide you with over 3 grams of fiber, but remember the fiber in potatoes is mostly in their skin. If you want the cholesterol-lowering, colon cancer preventing, and bowel supportive effects of fiber, be sure to eat the potato’s flavorful skin as well as its creamy center.
Potatoes are Rich in Vitamin B6—Athletic Performance
Vitamin B6 is also necessary for the breakdown of glycogen, the form in which sugar is stored in our muscle cells and liver, so this vitamin is a key player in athletic performance and endurance.
How to Select and Store
While potatoes are often conveniently packaged in a plastic bag, it is usually better to buy them individually from a bulk display. Not only will this allow you to better inspect the potatoes for signs of decay or damage, but many times, the plastic bags are not perforated and cause a build up of moisture that can negatively affect the potatoes.
Potatoes should be firm, well shaped and relatively smooth, and should be free of decay that often manifests as wet or dry rot. In addition, they should not be sprouting or have green coloration since this indicates that they may contain the toxic alkaloid solanine that has been found to not only impart an undesirable taste, but can also cause a host of different health conditions such as circulatory and respiratory depression, headaches and diarrhea.
Sometimes stores will offer already cleaned potatoes. These should be avoided since when their protective coating is removed by washing, potatoes are more vulnerable to bacteria. In addition, already cleaned potatoes are also more expensive, and since you will have to wash them again before cooking, you will be paying an unnecessary additional cost.
Since new potatoes are harvested before they are fully mature, they are much more susceptible to damage. Be especially careful when purchasing these to buy ones that are free from discoloration and injury.
At WHFoods, we encourage the purchase of certified organically grown foods, and potatoes are no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including potatoes. In many cases, you may be able to find a local organic grower who sells potatoes but has not applied for formal organic certification either through the U.S. Department of Agriculture (USDA) or through a state agency. (Examples of states offering state-certified organic foods include California, New York, Oregon, Vermont, and Washington.) However, if you are shopping in a large supermarket, your most reliable source of organically grown potatoes is very likely to be potatoes that display the USDA organic logo.
The ideal way to store potatoes is in a dark, dry place between 45F to 50F (between 7-10C) as higher temperatures, even room temperature, will cause the potatoes to sprout and dehydrate prematurely. While most people do not have root cellars that provide this type of environment, to maximize the potato’s quality and storage, you should aim to find a place as close as possible to these conditions. Storing them in a cool, dark closet or basement may be suitable alternatives. Potatoes should definitely not be exposed to sunlight as this can cause the development of the toxic alkaloid solanine to form.
Potatoes should not be stored in the refrigerator, as their starch content will turn to sugar giving them an undesirable taste. In addition, do not store potatoes near onions, as the gases that they each emit will cause the degradation of one another. Wherever you store them, they should be kept in a burlap or paper bag.
Mature potatoes stored properly can keep up to two months. Check on the potatoes frequently, removing any that have sprouted or shriveled as spoiled ones can quickly affect the quality of the others. New potatoes are much more perishable and will only keep for one week.
Cooked potatoes will keep fresh in the refrigerator for several days. Potatoes do not freeze well.
Potatoes are a very good source of vitamin B6 and a good source of potassium, copper, vitamin C, manganese, phosphorus, niacin, dietary fiber and pantothenic acid.