HerbalEGram: Volume 13, Issue 1, January 2016 |
Editor’s Note: Each
month, HerbalEGram highlights a conventional food and briefly explores its
history, traditional uses, nutritional profile, and modern medicinal research.
We also feature a nutritious recipe for an easy-to-prepare dish with each
article to encourage readers to experience the extensive benefits of these
whole foods. With this series, we hope our readers will gain a new appreciation
for the foods they see at the supermarket and frequently include in their
diets.
The basic materials for this series were compiled by dietetic interns from
Texas State University in San Marcos and the University of Texas at Austin
through the American Botanical Council’s (ABC’s) Dietetic Internship Program,
led by ABC Education Coordinator Jenny Perez. We
thank Lindsey Duree (TSU, 2013) for her research and work on beets.
History and Traditional Use
Range and Habitat
The garden, or sugar, beet (Beta vulgaris,
Chenopodiaceae) is an annual vegetable which forms a dense cluster of dark
green leaves attached to a large, bulbous root.1 Both greens (aerial
parts) and roots are edible. Beets typically are grown in the spring and fall;
they thrive in cool seasons. In warmer climates, beets are grown in the winter
as well. The leaves can grow up to 18 inches tall, though they are best
harvested at two to three inches. The plant produces red-tinged green flowers.
Though red beetroots are most commonly available commercially, golden and
“candy cane” red and white roots also exist. The United States, France, Poland,
Germany, and Russia currently are the leading producers of beets.2
Selective breeding has produced several different varietals of Beta vulgaris, including sugar beet
(used for sugar extraction), mangel-wurzel (used as livestock fodder), and Swiss
chard (B. vulgaris subsp. cicla).1 Current research
suggests that these varietals may help post-exercise muscle recovery, improve
blood pressure, and combat dyslipidemia.
Phytochemicals and Constituents
Beets are nutritionally diverse, low in calories, cholesterol-free, and
fat-free. Beet greens also are edible and contain calcium, vitamin A and
carotenoids, vitamin C, and iron. 100 grams of beet greens contain 50% of the
United States Department of Agriculture’s (USDA’s) Recommended Daily Allowance
for vitamin C.2 Beetroots are a good source of folic acid, fiber,
potassium, and manganese.3 They are also rich in niacin, vitamin
B-6, pantothenic acid, iron, copper, magnesium, and manganese.
Like carrots, the color of beetroots indicates the different nutrient compounds
contained within. Red beets contain phytochemicals called betalains*, which can
also be found in Swiss chard, rhubarb (Rheum
rhabarbarum, R. rhaponticum,
Polygonaceae), and prickly pear cactus (Opuntia
ficus-indica, Cactaceae).4 Betanin, one of the most-studied
betalains, has been shown to provide anti-inflammatory support in vitro and in
animal models. Red beets contain 300-600 mg/kg of betanin, which gives this
variety its signature ruby-red color. This is slightly unusual, since most red-colored
foods owe their pigmentation to anthocyanins, another prevalent group of
compounds with antioxidant actions. However, betanin has exceptionally high
antioxidant activity, exhibiting 1.5-2 times more activity than its anthocyanin
counterparts.
Golden, or yellow, beetroots have greater concentrations of lutein than red
beets. In the human body, lutein is found in high concentrations in the retina
of the eye, and may help protect the eye from abnormal light sensitivity and
degenerative diseases such as cataracts and macular degeneration. Beet greens
contain higher levels of lutein and zeaxanthin, a similar carotenoid that also
promotes healthy vision.
Historical and Commercial Uses
Beets were first cultivated in the Mediterranean region and have a history of
use that dates back over 4,000 years.5 Modern cultivated beets are
descendants from a wild plant called the sea beet (B. vulgaris subsp. maritima), which
grew wild in North Africa and on the Mediterranean coast.1
Initially, humans consumed only the greens, and the root was used for medicinal
purposes or animal fodder.
Greek and Roman authors, including Theophrastus (3rd century BCE), Hippocrates
(4th century BCE), Dioscorides (1st century CE), and Pliny the Elder (1st
century CE), noted a wide variety of ailments they claimed could be cured or
prevented by beetroot and greens consumption.6 The primary medicinal
use of the beet was to detoxify the blood and cleanse the kidneys, liver,
bowel, and gallbladder. Beets also were believed to contain aphrodisiac
qualities, and carvings of beets were found on excavated frescoes from Greek
brothels.7 Other conditions thought to be treated using beets
included leprosy, wounds and skin disorders, dandruff, digestive issues, and
earaches.6
Trade throughout Europe spread the growth of beets beyond the Mediterranean
area, and the roots eventually evolved into the sweeter, more edible modern
plant.4 The popularity of beets increased around the 16th century
due to this careful cultivation. The high sugar content of the root made beets
a significant economic crop in Europe in the 19th century as an alternative
sweetener in the place of sugarcane (Saccharum officinarum, Poaceae). Currently, about 20-30% of the world’s
sugar production comes from sugar beets.7
Today, the root and greens are consumed as a food product.8 The root
can be prepared by boiling, roasting, baking, or pickling. Raw roots often are
added to salads and soups. The greens can be prepared as any other bitter
green, such as collard greens (Brassica
oleracea, var. acephala,
Brassicaceae). Beet juice and extract also are used as natural alternatives to
red food dye and in various cosmetic products.9
Modern Research
Current research shows that supplementation with beet juice has been shown to
play a role in human exercise tolerance and recovery. One human study concluded
that beet juice supplementation reduced the negative effects associated with
muscle hypoxia after exercise.10 Muscle hypoxia occurs when adequate
oxygen is not available for normal muscle activity. This impairs exercise
tolerance and energy production from muscles. Another clinical trial reported
that supplementation of beetroot juice for three days prior to strenuous
exercise reduced the amount of oxygen spent and increased exercise endurance by
reducing the time of muscle failure onset.11 This effect remained
true during moderate exercise as well.
Beets can affect blood pressure and dyslipidemia (a high level of cholesterol,
triglycerides, or both in the blood), due to their high nitrate concentration.
Dietary nitrates are converted to nitrites, which are known vasodilators
(compounds which cause blood vessels to expand), in the body upon ingestion.
Consumption of beet juice thus increases the concentration of plasma nitrites
in the blood, which decreases blood pressure in healthy adults. When studying
this effect, scientists also concluded that beet juice is protective against
endothelial (related to the inner lining of arteries) damage, finding a
decrease in systolic blood pressure by 6 mmHg after supplementation with
beetroot juice.12
The nitrates in beets also aid in smooth muscle relaxation, further adding to
its value as an exercise supplement.2 Professional and amateur
athletes are increasingly adding beetroot juice to their exercise regimen,
claiming an increase in stamina and decision-making speed following a promising
2015 study.13 Researchers concluded that after a week of
supplementation with beet juice, healthy male subjects showed increased
reaction time and athletic performance during a sprinting exercise.14
Another study showed a significant decrease in blood pressure, with a change of
10.4 mmHg systolic and 8 mmHg diastolic measurements, due to the high nitrate
concentration in beets. This study also suggested that beets can prevent
endothelial dysfunction and inhibit platelet aggregation. These effects were
attributed to the ingestion of nitrates that are converted to nitrites and then
reduced to nitric oxide in the stomach.15 Supplementation of
beetroot, combined with hawthorn (Crataegus
spp, Rosaceae) berry, increased plasma nitrate and nitrite concentrations,
and significantly reduced triglyceride levels in 72% of participants with
elevated triglycerides.16
Health Considerations
Eating a moderate amount of red beetroots or products colored with red beet
extract may cause some individuals to experience a temporary reddening of the
urine.4 This is known as “beeturia” and is not harmful. However, it
may also be an indication of abnormal iron levels in the body or of a problem
with iron metabolism, as those with these pre-existing conditions are more
likely to experience “beeturia.”
Both root and greens of beets contain a high amount of oxalates, which may
exacerbate conditions such as kidney stones. However, since beets also contain
a high ratio of minerals to oxalates, the amount of bioavailability may be
lower than foods with similar oxalic contents.17,18
* Betalains were first named as a unique set of
pigments in 1968 by Andre Dreiding and the late Professor Tom J.
Mabry, PhD, of the Department of Botany at the University of Texas at Austin. A
world-renowned phytochemist and scholar, Mabry passed away in November 2015.
Among his many academic distinctions and memberships, he was a former member of
the ABC Advisory Board.
Nutrient Profile3
Macronutrient Profile: (Per 100g [approx. 3/4 cup] raw beetroot)
43 calories
1.61 g protein 9.56 g carbohydrate 0.17 g fat
Secondary Metabolites: (Per 100g [approx. 3/4 cup] raw beetroot)
Excellent source
of:
Folate: 109 mcg (27.25% DV)
Very good source
of:
Manganese: 0.32 mg (16% DV) Dietary Fiber: 2.8 g (11.2% DV)
Good source of:
Potassium: 325 mg (9.3% DV) Vitamin C: 4.9 mg (8.17% DV) Magnesium: 23 mg (5.75% DV)
Also provides:
Iron: 0.8 mg (4.44% DV) Phosphorus: 40 mg (4% DV) Vitamin B6: 0.07 mg (3.5% DV) Riboflavin: 0.04 mg (2.35% DV) Zinc: 0.35 mg (2.33% DV) Thiamin: 0.03 mg (2% DV) Niacin: 0.33 mg (1.65% DV) Calcium: 16 mg (1.6% DV)
DV = Daily Value as established by the US Food and Drug
Administration, based on a 2,000 calorie diet.
Recipe: Roasted Beets with Orange-Balsamic Glaze
Ingredients:
Directions:
—Hannah Bauman
References
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Wednesday, 6 April 2016
Food as Medicine Beets (Beta vulgaris, Chenopodiaceae)
