Page 22 - North Haven Magazine Issue 21 Holiday 2021

by Sally Brockett
Sweet Potatovs.Yam

Do you know which you are eating?

ncreasing numbers of people are eating sweet potatoes
Ibecause medical and nutrition articles recommend the
food as a healthy choice. But we see the term yam and
sweet potato used interchangeably. Is sweet potato just
another name for a yam? Does the difference in terms
just depend on what part of the country you live in? Is
there any difference in the nutritional value between
these two vegetables? It is important to look at this in-
formation because there really is a difference.

What is a sweet potato? sweetness! They are low in fat, but provide bryonic seed leaf, and belongs to the yam
A sweet potato is a dicot, a plant which has carbohydrates, an important source of en- family, closely related to lilies and grasses.
two embryonic seed leaves, and is a large ergy, and valuable fiber, which helps control Nearly all the 600+ varieties are grown in
edible root tuber within the morning glo- blood sugar. Africa. Yams are starchy tubers and have
ry family. There are many varieties of sweet thick, brown, bark-like skin. The flesh is
potatoes, and the skin color ranges from How cooking affects a sweet potato drier than sweet potatoes with yellow, off-
white to yellow, red, purple, or brown. The Despite all the good nutrients, be aware white, red, or purple color. Even if labeled
flesh of the sweet potato can also range from that sweet potatoes can have a high glyce- as a “yam,” if it is in a U.S. supermarket, it is
white to yellow, orange, or orange-red. In mic load depending on how it is cooked. most likely a sweet potato.
addition to skin and flesh color differences, The glycemic index (GI) ranks carbohy-
sweet potatoes are classified as either firm drate-containing foods according to the Nutritional value of yams
or soft, according to the consistency of the immediate effect that food has on blood The health benefits of yams have not been
flesh after cooking. Soft varieties become sugar levels. Foods with a low GI level do studied as extensively as sweet potatoes,
soft and moist after cooking and are often not cause blood sugar levels to spike. Both possibly because yams are not as readily
called yams in the United States. sweet potatoes and yams fall in the mid- available in U.S. markets. However, yams
range of the GI. contain less beta carotene, and less Vita-
History of the sweet potatoes min C. Yams and sweet potatoes are about
The firm varieties of sweet potatoes were equivalent in fiber, and both are exception-
produced first in the United States. Later, ally low in fat, unless topped with lots of
soft varieties were introduced, creating a butter, or sour cream!
need to distinguish between the two. Af-
rican slaves were already using the term Cooking with yams
“yams” because the soft sweet potatoes While sweet potatoes can be eaten raw, cer-
were similar to the “yams” in Africa, so the tain kinds of yams must be cooked before
soft varieties became known as yams. Cur- eating. A naturally occurring plant protein
rently, the U.S. Department of Agriculture is contained in some types of yams, which
requires that the name “yam” be accom- is removed by peeling and cooking the yam.
panied by the term sweet potato. Yams are This is not a major problem because we typ-
more often found in international markets ically purchase and eat sweet potatoes, and
while sweet potatoes are generally in the Sweet Potato Soup most people do not consume yams or sweet
U.S. supermarkets. potatoes raw, but it is good to be aware of.
The method of cooking a sweet potato af-
Nutritional value of sweet potatoes fects the glycemic index due to the way
Sweet potatoes provide significant levels heat breaks down the starch. The GI level
of Vitamin A in the form of beta-caro- increases with longer exposure to heat. Al-
tene, especially if the flesh is a rich orange though there is variation in the GI depend-
color. One serving supplies 100% of your ing on the variety of sweet potato, the fol-
daily Vitamin A. The variety with purple lowing data will illustrate how heat impacts
flesh provides more anthocyanins, so color the GI. A study in the Journal of Food Pro-
makes a difference in the type of nutrient cessing and Technology reported that a raw
you get from the plant. Sweet potatoes are sweet potato has a GI of 15, microwaving
also a useful source of Vitamin B6, Vitamin increases the GI to 18, and baking increases
C, potassium, and fiber. it to 33. So don’t miss out on the nutrition- Sweet Potato Pie
al benefits but be aware of the impact that
Sweet potatoes live up to their name in cooking methods have on the GI. Sweet potatoes – a fall and winter favor-
terms of sugar content. With sixteen grams ite in the kitchen: now that the differences
of sugar, you really do not need to use What is a yam? between sweet potatoes and yams are clear,
marshmallows or brown sugar for any extra A yam is a monocot, having only one em- it is an appropriate time to think about rec-

22 North Haven Magazine - Holiday Issue 2021