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Functional Foods
Wayne Coates
Professor Emeritus
The University of Arizona
Chia (Salvia hispanica L.) is one of the
best, if not the best, functional food in the marketplace today.
What is a functional food?
A functional food can
be defined as a food which has one or more health-promoting and/or
disease-preventing components. Hence a functional food goes beyond the basic
function of supplying nutrients.
There are four types of functional foods:
-
Basic Foods - a natural, raw food with nothing
added (eg. chia seed)
-
Processed Foods with Added Ingredients - (eg. a
juice to which calcium has been added)
-
Foods With
Increased Functional Attributes - brought about by plant breeding, feeding animals special rations, or genetic engineering, (eg, feeding chia
to chickens so as to improve egg and/or meat
quality)
-
Isolated or Purified
Preparations - derived from foods (eg. omega-3 fish oils)
Chia falls into two of the four functional food
groups. Not only is it a functional food in its raw form, but it can be fed to
animals to make healthier products. Given that the FDA has classified chia as a
food, and it has no known limitations in terms of consumption. What this means
is that it can be freely consumed without concern. This is unlike a number of
other functional foods which in their whole or modified forms if overeaten can
be harmful or even toxic.
Another advantage chia seed has is that it is
essentially flavorless, so it can be added to any other food and will not change
its flavor. Additionally the seed does not have to be ground, but if ground will
still have a long shelf due to the presence of natural antioxidants. This is
unlike flaxseed, for example, which must be ground daily to prevent oxidation,
or if bought ground has had some type of stabilizer added, thereby no longer
making it a Basic Functional Food.
What are some components of functional foods, and
how can these improve your health?
Fiber
Chia contains both insoluble and soluble fiber,
with both components varying in amounts depending upon growing location and
environmental conditions during the growth cycle. In general total fiber content
is approximately 28 to 32 percent, with the insoluble portion ranging from 3.5
to 4.5 percent.
The general health benefits of fiber
are:
-
Insoluble - reduced risk of breast and colon
cancer
-
Soluble - reduced risk of cardiovascular disease and some
cancers
More specifically the health benefits
of consuming fiber are:
-
Fiber is important for gastrointestinal health
and plays an important role in normal laxation. A larger and softer mass
produced by consuming fiber-containing foods causes the large intestine to contract and move the contents towards excretion more rapidly.
-
Consumption of foods containing
fiber has been associated with a reduced risk of
type 2 diabetes. This is thought to occur by the
fiber helping to normalize the glucose response and
decrease insulin concentration and requirements.
-
Meals rich in fiber are processed
more slowly by the body, provide more volume
compared to lower fiber meals, and tend to produce a
feeling of fullness with fewer calories. In
addition, high fiber foods require more chewing and
take longer to eat, thus potentially limiting total
energy intake. All of these characteristics combine
to provide a means of weight control.
-
Evidence for fiber’s role in
reducing the risk of coronary heart disease (CHD) is strong enough that a recommended adequate intake for
fiber has been established. Additionally studies have revealed that viscous
fibers, like the soluble fiber in chia, are most effective in reducing blood
cholesterol levels.
Omega 3 Fatty Acids
Chia contains one of the highest, if
not the highest, amount of omega 3 fatty acids known in the plant world. As with
fiber the amount of omega 3 fatty acid in the seed varies with planting location
and environment during the growing season. In general the amount ranges from 58
to 65% of the total oil content, with the latter value ranging from 30 to 35%.
The omega 3 fatty acid found in chia, which is
known as alpha linolenic fatty acid (ALA) is the only essential omega 3 fatty
acid. This means a person must consume this fatty acid, since the body cannot
manufacture it. This is unlike EPA and DHA (which come from marine sources)
which the body manufactures from ALA. There is much discussion about how much
ALA is converted to EPA and DHA, with the general consensus being that everyone
converts differently, with the amount regulated by what the body needs. The only
external factor that affects conversion is over-consumption of omega 6 fatty
acids This occurs since the enzymes that convert ALA also convert omega 6 fatty
acids. If too many are expended in the omega 6 conversion, less ALA will be
converted.
The general benefits of consuming
omega 3 fatty acids are reduced risk of cardiovascular disease, improved mental
functions.
More specifically the health benefits
of consuming omega 3 fatty acids are:
-
A decrease in serum triglyceride and total
cholesterol levels, with a potential increase or no effect on
high-density-lipoprotein (HDL) cholesterol.
-
A potential reduction in the
symptoms of hypertension, depression, joint pain and
other rheumatoid problems.
-
A reduction in the symptoms of
attention deficit hyperactivity disorder (ADHD),
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Boosting the immune system, and
offering protection from an array of illnesses,
including Alzheimer’s disease.
-
In young children, omega-3 fatty
acids also aid in neurological development.
There is also evidence that a
shortage of omega3 fatty acids in the diet leads to low leptin levels in the
body. Low leptin levels have been shown to signal the brain to deposit fat to
increase energy reserves in the body. Thus an adequate intake of omega3 fatty
acids may aid in weight management.
Antioxidants and Phytochemicals
These two components have recently
been recognized as being important to human health, but are not necessary for
life. In some cases these terms have been used interchangeably. Of interest is
the fact that Phytochemicals (or sometimes called Phytonutrients) may act as
antioxidants, but not all phytochemicals are antioxidants.
Antioxidants are a much more
complicated components in terms of their composition, potential benefits, etc.
One measure that has been developed to describe overall antioxidant capacity of
foods is called Oxygen Radical Absorbance Capacity (ORAC). Chia seed has a
relatively high ORAC value, ranging from 60 to 85 μmoles TE/g, with growing
location and climate affecting the value. With chia seed there is another
important attribute that affects ORAC value, that is seed color. In general
darker colored foods have a higher ORAC value than lighter colored foods. This
applies to chia seed as well with the black seed having a higher value than the
white.
When looking at antioxidants in foods
they can be divided into two main groups or categories, with each having similar
and as well as different benefits in terms of human health. The two groups and
their general benefits are as follows:
Vitamins and Minerals - protects cells from free
radicals which can cause oxidative stress or damage to cells in the body
Phenols or Phenolic Compounds - reduced risk of
cardiovascular heart disease and cancer, protect cells from free radicals
As noted earlier, the classification system used
to describe antioxidants in foods is not a simple one, since there are many
subcategories under the two main categories. Within the vitamins and minerals
group are four major constituents: Vitamins A, C, and E along with Selenium.
Chia is not a particularly important source of any of these components, although
all are present.
It is the second category, the phenolics, which
chia contains significant amounts of. Within this group are several
sub-categories, with Phenolics or Polyphenols being divided into tannins and
phenylpropanoids. Within the latter group are the flavonoids, which include
several thousand compounds, including flavonols, flavones, catechins, flavanones,
anthocyanidins, and isoflavonoids. Chia contains a number of these compounds
including the flavonoids: Quercetin, Kaempferol, Myricetin; the phenolic acids:
Ferulic, Caffeic, p-Coumaric and chlorogenic; along with Catechins; and Phytic
acid.
More specifically the health benefits
of consuming antioxidants are as follows:
-
Oxidative stress arising from the presence of
free radicals is associated with a number of degenerative diseases that come
with aging including:
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cancer
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cardiovascular disease
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cognitive impairment
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Alzheimer’s disease
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Parkinson’s disease
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immune dysfunction
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cataracts
-
macular degeneration
-
Antioxidants have been shown to reduce oxidative stress,
and hence help to prevent onset of these diseases.
What else about chia makes it a great food?
Protein
Chia is a great
source of protein. It contains approximately 20% or more protein. This is more
than wheat which is around 14%.
Not only is the
amount of protein important, quality of protein is even more important. Protein
quality is based on a scoring method that looks at the essential amino acids
that make up the protein. This determines whether or not it is a high-quality or
a complete protein. Lysine tends to be the most common limiting amino acid, and
this is the case with both wheat and chia. The amino acid score for wheat is
around 55, whereas for chia it is 91. Thus both the quality and quantity of chia
protein is better than that of wheat.
Vitamins and Minerals
As noted earlier
chia is not a particularly good source of the vitamins that act as antioxidants,
but it does contain a reasonable amount of Niacin and Folic Acid. In terms of
minerals it is a good source of Calcium, Magnesium, Iron and Potassium, plus it
is relatively low in Sodium.
Other aspects of chia which make it a great and safe food
Chia is
cholesterol, trans fat and gluten free. Not only does this mean consumption of
chia will not increase a person’s risk of suffering coronary heart disease, but
it means it is safe for individuals suffering from celiac disease.
Additionally
limited allergen tests have shown no reactions to chia, even in nut sensitive
individuals, making this a very safe food for people of all ages.
As a final note
the FDA in 2005 confirmed in a letter to Dr. Wayne Coates that chia is a food
and is safe to eat. The letter stated in part:
“Chia is
considered a food”
and
“chia has been consumed by native cultures for
long periods of time, and we are not aware of any safety concerns”
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