Cultivation of sweet potatoes, which are native to Peru, dates
back to 750 BCE. Discovered by Columbus, sweet potatoes, often
(wrongly) called yams, belong to the Convolvulaceae, or morning
glory plant family. Yams (from the African word "nyami"), which are
from the Dioscoreae family, have only one embryonic seed
leaf, while sweet potatoes have two. Another note for consumers:
yams are usually more moist.
There are about 400 varieties of sweet potato, some more rare
than others, differentiated by their skin and flesh color, ranging
from cream, yellow, and orange to pink or purple. Oxidation turns
them dark in spots after peeling, so it's best to bake or steam
immediately, or place in water until you do.
Baked sweet potatoes are a lovely alternative to plain white,
especially with butter, salt, and pepper. Sweet potato chips and
fries (cooked in coconut oil) are tasty snacks. Boiling isn't
recommended because of potentially lost nutrients.
It's good to know that the health benefits of sweet potatoes may
even surpass their reputation as a holiday favorite, having unique
attributes not seen in other plant-based foods.
Health Benefits of Sweet Potatoes
The deep orange color is more than just different than white
potatoes; it's one of the indications of beta-carotene presence,
shown by numerous studies to be especially rich in sweet potatoes.
The vitamin A per serving even rivals that of green leafy vegetables
(yams only have 3%!), providing 769% of the daily value per serving.
In fact, the only food that has more vitamin A is three ounces of
beef liver! The 65% daily value of vitamin C and 29% DV of vitamin
B6 isn't too bad, either.
Two key antioxidant enzymes in sweet potatoes are copper/zinc
superoxide dismutase and catalase. One study showed purple sweet
potatoes to have more than three times the antioxidant activity than
that of one type of blueberry.
Especially in light of their high sugar content, a surprising
fact about sweet potatoes is their ability to help regulate blood
sugar, even in type 2 diabetes patients. Research has verified that
sweet potato extract can increase blood levels of adiponectin, a
protein hormone produced by your fat cells, to regulate the way your
body metabolize insulin, and even lower insulin levels when needed.
However, make sure you consume sweet potatoes in moderation, as
some varieties are high in fructose. In fact, the American sweet
potato has been literally bred for sweetness, with 6.5 grams of
sugar per 100 grams.
Sweet Potatoes Nutrition Facts
One cup of baked sweet potatoes (200 grams)
Amt. Per Serving
Calories
180
Carbohydrates
41 g
Sugar
13 g
Fiber
7 g
Protein
4 g
Studies Done on Sweet Potatoes
Studies show that heat processing methods for sweet potatoes,
such as steaming, baking, or boiling as opposed to raw, not only
releases beta-carotenes, but also makes them more accessible to the
body,1
possibly because heat causes a disruption in the microstructure of
the tissue.
Other studies have demonstrated that sweet potato extract has
anti-obesity and anti-inflammatory potential, reducing inflammation
in brain tissue and nerve tissue throughout the body.2
Anthocyanidins, responsible for the pigmentation of deeply-hued
vegetables like purple sweet potatoes, contain flavonoid and
antioxidant wound-healing properties. Studies have attributed
anthocyanidins for suppressing stomach, colon, lung, and breast
cancer cell growth. Because they also prevent platelets from
sticking together, they prevent blood clots, which may in turn help
fight heart disease.
Other polyphenols in purple sweet potatoes include cyanidins and
peonidins, which studies indicate have strong counter effects on
cancer cell growth. Interestingly, these anti-cancer compounds are
more concentrated in the sweet potato itself than the skin,4
and may also lower the dangers posed by heavy metals and oxygen
radicals, including mercury, cadmium, and arsenic.
Research in another study showed both benign and cancerous
colorectal tumors to multiply in the presence of substances such as
pyridine, (structurally related to benzene and ammonia) and
dimethylhydrazine (a rocket propellant), but these toxins were
inhibited by introducing purple sweet potato.4
The results "clearly demonstrated" that purple sweet potato has the
capacity to reduce colorectal carcinogens.
2 or 3 sweet potatoes, peeled and cut into 1-2 inch pieces
Unsweetened, flaked coconut
1 one-pint container of plain Greek yogurt
1 Tbsp. coconut oil
Procedure:
Pre-heat grill to medium-high. Steam sweet potato chunks in
a small amount of water, stovetop, for 10 minutes.
Allow to cool. Place the sweet potato chunks on wooden or
metal skewers, baste them with Greek yogurt, drizzle with
coconut oil, and then grill until lightly browned and crispy on
the surface (about 4 minutes on each side).
Roll the entire skewer gently on a plate liberally sprinkled
with the coconut flakes. Season with salt if desired. Easy and
delectable!
Sweet Potatoes Fun Facts
Sweet potatoes were transported to Spain, probably by Columbus,
in about 1500. Several varieties, including purple and red, were
cultivated there by the mid-16th century. Other Spanish explorers
carried the orange and purple-hued tubers to the Philippines and
East Indies, and from there cultivation spread to India, China, and
beyond, via Portuguese voyagers.
In 1740s, "sweet" potatoes became known as such in the American
colonies to distinguish them from white "Irish" potatoes.
Summary
Don't just serve deliciously honeyed or savory sweet potatoes on
holidays; enjoy them regularly in a plethora of ways – sautéed,
baked, steamed, or fried – because they're good for you!
Antioxidants take the bite out of free radicals roaming throughout
your body looking for a place to cause damage, but that's just one
of the tremendous health benefits you get from sweet potatoes.
Anthocyanidins, which give them deep pigments such as orange and
purple, contain flavonoid and antioxidant clotting, wound-healing,
and heavy metal cleansing properties.
Sweet potatoes come with super strong beta-carotenes, along with
copper/zinc superoxide dismutase and catalase, adiponectin for
balancing your insulin, impressive doses of vitamin A, plus good
levels of vitamin C and vitamin B6. Studies have proven both orange
and purple sweet potatoes to be cancer fighters, but purple sweet
potatoes include cyanidins and peonidins for extra protection.
Including three to five grams of (good) fat with every meal
significantly increases your beta-carotene uptake from sweet
potatoes, easily done by using one tablespoon of extra virgin olive
oil.