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 would like to acknowledge Perez, ABC Special Projects Director Gayle Engels,
and ABC Chief Science Officer Stefan Gafner, PhD, for their contributions to
this project.
By Hannah Baumana
and Juliette Coronadob
a
HerbalGram Associate Editor
b ABC Dietetics
Intern (Texas State, 2016)
Overview
Chia (Salvia hispanica, Lamiaceae) is an
annual herb native to Mexico and Guatemala that requires fertile, well-drained
soil and subtropical climate conditions to set seed in the late summer months
of July and August.1-4 Chia is the most common name for this plant,
but it is also sometimes called Spanish sage, lime-leaf sage, Mexican chia, and
black chia.2,4 The plant grows to three feet (0.9 meters) tall when
mature, and has opposite, serrated leaves that are 1.5-3 inches (3.8-7.6 cm)
long and 1-2 inches (2.5-5 cm) wide, and produces small white or purple flowers
on the tips of its terminal stems.2,4,5 Chia’s leaves contain
essential oil that acts as a defense mechanism to repel insects.2
The edible part of the chia plant is the seeds,5-7 which are small
(2 mm in length), flat, and oval-shaped.2 Although dark chia seeds
are predominantly gray with dark spots,7 they can also appear white,
black, black spotted, or dark brown, and may differ slightly in size and weight.2,5
Phytochemicals
and Constituents
Chia
seed has high levels of protein, omega-3 fatty acids, fiber, and specific
vitamins and minerals.2,7 The seed also contains all essential amino
acids and is high in antioxidants.8 A gram of chia seeds contains about
0.28 g fiber, 0.21 g protein, and 0.6 g/g of the omega-3 fatty acid alpha-linolenic
acid (ALA), which is the highest proportion of ALA of any known plant source.9
Chia seed and its oil have an abundance of polyunsaturated fatty acids (PUFAs).
ALA is the most predominant fatty acid found in chia, followed by the omega-6 fatty
acids linoleic acid and oleic acid.
Omega-6 fatty acids
have pro-inflammatory, hypertensive, and prothrombotic properties.5
Omega-3 fatty acids, however, are associated with numerous health benefits and
have anti-inflammatory, anti-diabetic, lipid-lowering, cardioprotective, and
hepatoprotective properties. For maintenance of good health, omega-3 fatty
acids should be incorporated in the diet at higher amounts than omega-6 fatty
acids. The omega-3:omega-6 ratio found in chia seeds is about 3:1.6,7
The amount of oil within chia seed ranges from 25-40%.2,5
In comparable serving
sizes, the protein content of chia seeds exceeds that of seeds such as amaranth
(Amaranthus spp., Amaranthaceae) and
quinoa (Chenopodium quinoa,
Chenopodiaceae).2 The primary determinant of a high-quality protein
is its digestibility, or the amount of protein absorbed by the body relative to
the amount consumed. For chia seed flour, protein digestibility is nearly 80%,
which is comparable to processed cereal grains such as wheat (Triticum aestivum, Poaceae) and oats (Avena sativa, Poaceae); however, chia contains
a much higher percentage of protein per serving than these grains.10
Furthermore, chia seed contains high levels of the amino acids glutamic acid,
arginine, and aspartic acid.2 In addition to an abundance of these
non-essential amino acids, chia seed contains all nine essential amino acids
that the body is unable to produce and is therefore considered a complete
protein, unlike other plant protein sources such as chickpeas (Cicer arietinum, Fabaceae). Chia seed contains
low concentrations of prolamins (< 15%), which suggests that it can be
safely incorporated into the diet of patients with celiac disease.2,10
Approximately two
tablespoons (one ounce or about 28 grams) of chia seed provides almost 40% of an
average person’s daily fiber intake, as recommended by the US Food and Drug
Administration (FDA). Total dietary fiber includes both soluble and insoluble
forms that are important for reducing the risk of cardiovascular disease,
diabetes, and certain types of cancer.2 Compared to other foods,
chia seed contains more dietary fiber than an equivalent volume of flax (Linum usitatissimum, Linaceae) seed.
High fiber intake also promotes gastrointestinal and digestive health.
Chia seeds and oil are not only
known for their macronutrient and micronutrient contents, but also for their
antioxidant properties.7 Phenolic compounds present in chia have
been found to protect against certain diseases, such as cardiovascular disease
and diabetes.11 The most important polyphenols found in chia seeds
and seed oil include chlorogenic and caffeic acids, which play a crucial role
in the protection against free radicals and inhibit fat, protein, and DNA
peroxidation.2,11,12 The flavonols myricetin, quercetin, and
kaempferol are other active compounds present in chia seeds.7 Flavonols
are known for their antioxidant, cytotoxic, anti-inflammatory, and anti-thrombotic
effects.5,13 Researchers have found that these polyphenols and
others found in chia seed and seed oil (e.g., rosmarinic, protocatechuic, and
gallic acids) have a high antioxidant capacity.12,14
Historical
and Commercial Uses
Chia has been used by
Mesoamerican cultures for more than 1,000 years for medicinal, culinary,
artistic, and religious purposes.7,15 The Chumash and Cahuilla
peoples in the coastal southern regions of California cultivated chia for its
seeds, which were collected, hulled, and winnowed by hand.16 After
the introduction of wheat, chia was still a preferred crop, and small amounts
of chia flour were used to improve the flavor of wheat flour.
The seed of the chia
plant is the part most often used for medicinal purposes, but the root and
aerial parts were also used occasionally.15 Prior to Spanish
colonization in the 16th century, chia seed was used by native tribes to provide
energy, treat respiratory infections, and for obstetrics treatment. Prized by
Aztec warriors in central Mexico, chia seeds were eaten to promote endurance
and consumed with bread prior to battle or with water before running long
distances.8
The Diegueño people of
Baja California took chia seeds on journeys, kept a few seeds in the mouth and
periodically chewed them to maintain their strength.16 One
tablespoon of chia seed was believed to be sufficient to feed a person for a
day. After the 16th century, a mucilaginous
paste made from chia seeds and water was used therapeutically to treat eye obstructions and
infections.17 Medical uses of chia seed prior to Spanish
colonization included soothing skin conditions, treating gastrointestinal
conditions, lowering fevers, and as a poultice for open wounds.15,16
The chia seed has been
used for culinary purposes in multiple forms: whole, ground (flour), mucilage,
and oil.7,15 Seeds were ground into flour and used to make biscuits,
cakes, and a porridge called pinole.16
Traditional foods, such as tortillas and tamales, were made from chianpinolli, or roasted and ground chia
seed.15,17 Chia flour was used to make an array of beverages during
the height of the Aztec Empire, but modern use of this tradition has declined.15
The most recognized use of chia seeds in the 18th and 19th centuries was
infusing chia seeds in water, which was believed to make the alkaline desert
water taste more palatable. “Chia fresca,” or “agua de Chia,” was also a
popular, thirst-quenching beverage that combined chia seeds with fruit juices.15-17
Chia seed oil was also used for artistic purposes,
primarily in paints and lacquers to create a glossy finish on clay or gourd
vessels.15 The oil was also used as the basic ingredient for
ceremonial face or body paint. Chia-infused beverages were historically
consumed during ceremonies, festive occasions, and holy observances. Other
religious uses included the use of chia flour to make dough that was formed
into the shape of the goddess Chicomecoatl, the “maker and giver of things
necessary to live,” as an offering. With the rediscovery of chia as an
important food source, modern uses of chia seed and oil focus on its omega-3
fatty acid content for nutritional supplementation, and it is sold commercially
as cold-pressed seed oil or whole seeds as ingredients for baked goods, snacks,
bread, yogurt, and bars.2
In 1977, the Chia Pet, small hollow-bodied animal
figurines made out of terra cotta, became a registered trademark of Joseph
Enterprises, Inc.18 Moistened chia seeds are applied to the grooved
ridges on the outside of the figurine, and water is added to the hole inside
the figurine to help the seeds germinate. Within days, the figure grows a thick
coat of chia sprouts. For more than 30 years, Chia Pets have offered customers
amusement and an introductory lesson to the practice of cultivating plants.
Modern
Research
Cardiovascular
Disease Risk Factors
The nutrient profile
and bioactive compounds found in chia seed and oil have demonstrated
cardioprotective effects by reducing disease risk factors in humans.
Hypertension, a known risk factor for developing cardiovascular disease, is
generally asymptomatic and can be difficult to control with drug therapies
alone. Diet interventions can offer a complementary approach.19 Supplementation
with ground chia seed for 12 weeks was shown to reduce blood pressure in
individuals with treated and untreated hypertension. Participants in the study
were randomly assigned to one of three groups: consumption of chia with
previously used medications (CHIA-MD), chia without medications (CHIA-NM), or a
placebo group with medications (PLA-MD). Subjects in the two treatment groups
consumed 35 grams of chia flour per day. The PLA-MD group received 35 grams of
roasted wheat bran as a placebo. Researchers found that the two chia groups had
significantly reduced diastolic and systolic blood pressures from baseline. The
CHIA-MD group also had significantly reduced total blood pressure from
baseline.
A 2015 systematic
review investigated current literature on consumption of whole or ground chia
seeds and its effect on preventing or managing risk factors associated with
heart disease, such as hypertension, diabetes, dyslipidemia, and obesity.20
The review focused on seven clinical trials published between 2007 and 2013.
The chia seed preparations used in the studies varied in quantity (4-50 grams
per day) and type (e.g., whole or milled). There were also differences in
sample size, methodology, and participant characteristics (e.g., diabetic,
obese, hypertensive). Therefore, the authors state that the findings on chia consumption
and the effects of reducing cardiovascular risk factors are inconclusive. They recommend
additional randomized, double-blind, placebo-controlled clinical trials on the
consumption of chia to obtain reliable results and to determine an appropriate
dose for cardioprotective benefits.
Obesity is a condition
that has been associated with a state of chronic oxidative stress. Reactive
oxygen species damage cell proteins, lipids, and DNA, and can result in
impaired function and potentially cell death. Obesity also impedes the body’s
enzymatic antioxidant system, reducing the activities of catalase, superoxide
dismutase, glutathione peroxidase, and glutathione reductase.24
Additionally, obesity correlates with a reduction in levels of protective
thiols, vitamins, minerals, and polyphenols. A study on chia seed’s efficacy
for weight loss and decreasing disease risk factors in overweight adults found
increases in plasma ALA levels. However, consumption of chia seed in high doses
(50 grams per day) had no effect on weight loss or changes in disease risk
factors related to cardiovascular
disease (e.g., blood pressure, high-density and low-density lipoprotein, total
cholesterol, or blood triglyceride levels).21 Another randomized,
double-blind, placebo-controlled study assessed the effectiveness of
chia seed (whole or ground) supplementation for changing disease risk factors
for overweight women.22 For 10 weeks, participants consumed 25 grams
per day of ground or whole chia seeds or a placebo. Multiple outcome measures
were assessed, and researchers observed a 58% and 39% increase in plasma ALA
and eicosapentaenoic acid (EPA) levels, respectively, in the ground chia
treatment group.
Glucose
Levels
The use of chia as a
food ingredient holds promise in the area of so-called “functional foods.” A
2013 study observed the effects of bread supplemented with chia seed flour on
post-prandial (after-meal) blood sugar levels in healthy adults. Thirteen
healthy adults consumed nine test meals that included bread supplemented with
different doses (seven, 15, and 24 grams) of whole or ground chia.23
Bread without chia was used as the control. Researchers concluded there was a
significant dose-dependent effect on blood glucose levels for both whole and
ground seeds compared to the control, but no differences were evident between
the same doses of the whole and ground seed groups. This may indicate that the
quantity of seeds given in the diet will demonstrate hypoglycemic properties
and not the form in which chia is ingested. The seeds used in the study were a
specific varietal bred from black chia and proved effective for reducing blood
glucose levels, but future research is needed to further investigate the benefits of
different chia strains.
Antioxidant
Properties
Chia’s antioxidant
potential was analyzed in a 2015 rat study.24 Results demonstrated that daily
consumption of chia seed and chia seed oil enhanced plasma antioxidant levels
through catalase, glutathione peroxidase and thiol level reduction. Chia
seed and seed oil intake resulted in a significant reduction in plasma levels
of 8-isoprostane, the most specific biological indicator for assessing oxidative
stress in vivo. High levels of 8-isoprostane can occur with a diet high in
fat and fructose and result in pro-oxidative effects. This may be the mechanism by which chia seed and seed oil produces
a hypolipidemic effect. Lipid peroxidation in rat livers was not reversible;
however, levels of glutathione reductase were increased as well as thiol levels,
resulting in improved antioxidant status.
Other
Uses
Carbohydrate-loading
refers to the practice of increasing dietary intake of carbohydrates prior
to athletic events that last more than 90 minutes. This intake results in
greater capacity of muscle glycogen stores and aids in improved athletic
performance.8 A 2011 study compared performance test results of six
male marathon runners who were given two different carbohydrate-loading
treatments: a commercial sports drink and the same commercial sports drink
supplemented with chia. The runners participated in two trials in a crossover,
counterbalanced, repeated-measure design with a two-week washout period between
testing to allow participants to recover from the intense exercise and to avoid
any carry-over effects from the treatments. While the researchers found no
statistical difference between the control and the test groups in performance
parameters, the athletes in the chia group significantly decreased their
dietary intake of sugar while boosting intake of omega-3 fatty acids, which
indicates that the chia drink may be a healthier option for athletes who choose
to carbohydrate-load.
Chia seed oil is also
used topically. Approximately 30% of patients with diabetes or end-stage renal
disease (ESRD) suffer from skin disorders including pruritus, which is
characterized by itchy, dry skin and inflammatory lesions caused by scratching.13
This study followed five patients with these conditions (three with diabetes; two
with ESRD) and five patients without these conditions who all exhibited xerotic
pruritus (abnormally dry, itchy skin) for eight weeks. A topical oil and water
emulsion containing 4% chia seed oil was applied to affected skin. Lotion without
chia seed oil was used on participants as a placebo. After eight weeks of
application, statistically significant improvements in skin hydration, chronic
itching, and prurigo nodularis (hard, itchy lumps on the skin) were observed in
the treatment group with diabetes and ESRD, while similar significant
improvements in skin hydration and epidermal permeability were also observed in
the group of patients without these conditions.
Consumer
Considerations
Consumption
of whole or ground chia seed has shown no evidence of toxicity or allergenic
effects.2 However, the Dietary Guidelines for Americans, eighth edition, issued by the US Department of Health and Human Services and US Department of Agriculture listed a standard portion size of chia as one tablespoon (or roughly 50 grams) per day.25 This
may be due to clinical studies that have not exceeded a dose of 50 grams per day,
and thus the potential adverse effects have not been adequately studied above
this amount.
The PUFA content as
well as the low concentration of tocopherol and phenolic compounds account for
the low oxidative stability of chia oil. Within 300 days, a 30% drop in the
tocopherol content of chia seed oil was observed.9 The antioxidant
capacity of chia oil is relatively low due to the hydrophilic nature of the
phenolic compounds within the chia seed. Despite chia seed’s rich omega-3 and
omega-6 content, there is a technological disadvantage in the production of
chia seed oil in regards to its stability and short shelf life,
especially when exposed to light or oxygen. Chia seed oil is best kept in the
refrigerator after opening and should be used quickly to gain its full range of
nutrients.
Nutrient Profile26
Macronutrient
Profile: (Per 1
ounce seeds)
138 calories
4.7 g protein
11.9 g carbohydrate
8.7 g fat
Secondary
Metabolites: (Per 1
ounce seeds)
Excellent
source of:
Manganese: 0.8 mg (40%
DV)
Dietary Fiber: 9.8 g (39.2% DV)
Phosphorus: 244 mg (24.4% DV)
Magnesium: 95 mg (23.8% DV)
Very
good source of:
Calcium: 179 mg (17.9% DV)
Thiamin: 0.2 mg (13.3% DV)
Niacin: 2.5 mg (12.5% DV)
Iron: 2.2 mg (12.2% DV)
Also
provides:
Folate: 14 mcg (3.5% DV)
Potassium: 115 mg (3.3% DV)
Riboflavin: 0.05 mg (3% DV)
Trace
amounts of:
Vitamin C: 0.5 mg (0.8% DV)
Vitamin E: 0.14 mg (0.7% DV)
Vitamin A: 15 IU (0.3% DV)
DV = Daily Value as
established by the US Food and Drug Administration, based on a 2,000-calorie
diet.
Recipe: Strawberries and Cream Chia
Pudding
Adapted from Emily Han27
Ingredients:
- 8 ounces fresh
strawberries (Read more about the benefits of strawberries here.28)
- 3/4 cup coconut milk
- 2 tablespoons honey
- 1/2 teaspoon vanilla
extract
- 1/2 teaspoon grated
lime zest
- 1/4 cup chia seeds
Directions:
- Combine the
strawberries, coconut milk, honey, vanilla, and lime zest in a blender. Puree
until smooth. Taste and add more honey, if desired.
- Place the chia seeds
in a large bowl and add the strawberry mixture. Whisk thoroughly to combine.
Let the mixture stand for 10 minutes, then whisk again.
- Cover and refrigerate
for at least four hours and up to three days. Stir before serving. The pudding
will set up thicker the longer it sits.
Photo credits: Top: Salvia hispanica seeds. ©2017 Steven Foster.
Middle: Image of Salvia hispanica from the 16th-century Florentine Codex by Fr. Bernardino de Sahagún.
Bottom: Salvia hispanica seeds. ©2017 Steven Foster. References
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hispanica – L.
Plants for a Future website. Available at: www.pfaf.org/user/Plant.aspx?LatinName=Salvia+hispanica.
Accessed August 24, 2017.
- Muñoz LA, Cobos A,
Diaz O, Aguilera JM. Chia seed (Salvia
hispanica): An ancient grain and a new functional food. Food Reviews International.
2013;29:394-308.
- Taxon: Salvia hispanica L. US National Plant
Germplasm System website. Available at: https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?32939.
Accessed August 24, 2017.
- Kaiser C, Ernst M.
Center for Crop Diversification Crop Profile: Chia. Lexington, KY: University
of Kentucky College of Agriculture, Food and Environment. February 2016.
- Ali NM, Yeap SK, Ho
WY, Beh BK, Tan SW, Tan SG. The promising future of chia, Salvia hispanica L. Journal
of Biomedicine and Biotechnology. 2012;171956.
- Porras-Loaiza P,
Jiménez-Munguía MT, Sosa-Morales ME, Palou E, López-Malo A. Physical properties,
chemical characterization and fatty acid composition of Mexican chia (Salvia hispanica L.) seeds. International Journal of Food Science and
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- Valdivia-López MA,
Tecante A. Chia (Salvia hispanica): A
review of native Mexican seed and its nutritional and functional properties. Advances in Food and Nutrition Research.
2015;75:54-71.
- Illian TG, Casey JC,
Bishop PA. Omega 3 chia seed loading as a means of carbohydrate loading. Journal of Strength and Conditioning
Research. 2011;25(1):61-65.
- Bodoira RM, Penci MC,
Ribotta PD, Martínez ML. Chia (Salvia
hispanica L.) oil stability: Study of the effect of natural antioxidants. LWT – Food Science and Technology.
2017;75:107-113.
- Kačmárová K, Lavová B,
Socha P, Urminská D. Characterization of protein fractions and antioxidant
activity of chia seeds (Salvia hispanica
L.). Potravinarstvo.
2016;10(1):78-82.
- Pandey KB, Rizvi SI.
Plant polyphenols as dietary antioxidants in human health and disease. Oxidative Medicine and Cellular Longevity.
2009;2(5):270-278.
- da Silva Marineli R,
Moraes ÉA, Lenquiste SA, Godoy AT, Eberlin MN, Maróstica Jr MR. Chemical
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2014;59:1304-1310.
- Jeong SK, Park HJ,
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renal disease (ESRD) patients and healthy volunteers. Ann Dermatol. 2010;22(2):143-148.
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Paredes-López O. Phytochemical profile and nutraceutical potential of chia
seeds(Salvia hispanica L.) by ultra
high performance liquid chromatography. Journal
of Chromatography A. 2014;1346:43-48.
- Cahill J. Ethnobotany
of chia, Salvia hispanica L.
(Lamiaceae). Economic Botany. 2003;57(4):604-618.
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Chia. Washington DC: United States Department of Agriculture Natural Resources
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- Hershey DR. Don’t just
pet your chia. Science Activities.
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- Edwards O. Chia Pet. Smithsonian Magazine. December 2007.
Available at: www.smithsonianmag.com/arts-culture/chia-pet-180308610/.
Accessed August 24, 2017.
- Toscano LT, Oliveira
da Silva CS, Toscano LT, Monteiro de Almeida AE, Santos AdC, Silva AS. Chia
flour supplementation reduces blood pressure in hypertensive subjects. Plant Foods Hum Nutr. 2014;69:392-398.
- de Souza Ferreira C,
de Sousa Fomes LdF, Santo da Silva GE, Rosa G. Effect of chia seed (Salvia hispanica L.) consumption on
cardiovascular risk factors in humans: a systematic review. Nutrición Hospitalaria.
2015;32(5):1909-1918.
- Nieman DC, Cayea EJ,
Austin MD, Henson DA, McAnulty SR, Jin F. Chia seed does not promote weight
loss or alter disease risk factors in overweight adults. Nutrition Research. 2009;29:414-418.
- Nieman DC, Gillitt N,
Jin F, et al. Chia seed supplementation and disease risk factors in overweight
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Alt Complement Med. 2012;18(7):700-708.
- Ho H, Lee AS, Jovanonvski
E, Jenkins AL, DeSouza R, Vuksan V. Effect of whole and ground Salba seeds (Salvia hispanica L.) on postprandial
glycemia in healthy volunteers: A randomized controlled, dose-response trial. Eur J Clin Nutr. 2013;67:786-788.
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Lenquiste SA, Moraes ÉA, Maróstica Jr. MR. Antioxidant potential of dietary
chia seed and oil (Salvia hispanica
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- US Department of Health and Human Services and US Department of Agriculture. 2015-2020 Dietary Guidelines for Americans. 8th ed. December 2015. Available at: http://health.gov/dietaryguidelines/2015/guidelines. Accessed September 14, 2017.
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Seeds, chia seeds, dried. United States Department of Agriculture Agricultural
Research Service website. Available at: https://ndb.nal.usda.gov/ndb/foods/show/3610.
Accessed August 23, 2017.
- Han E. Dairy-Free
Dessert Recipe: Strawberries & “Cream” Chia Pudding. The Kitchn website.
May 8, 2013. Available at: www.thekitchn.com/recipe-strawberry-chia-pudding-recipes-from-the-kitchn-189016.
Accessed August 23, 2017.
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Food as Medicine: Strawberry (Fragaria x ananassa, Rosaceae). HerbalEGram.
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