The decision to
improve one’s health typically includes a form of dietary intervention and many
popular or “fad” diets accomplish the goal of weight loss through the
manipulation of Caloric content in a meal. Although the total Calories or energy
in a food item is important for weight manipulation, the composition of a food
item in terms of its nutrient content or density is equally as important.
However, many times when individuals make a food selection, he or she is more
concerned with the total caloric content instead of what type and how many
different nutrients can I get out of a particular food item. This brings me to
the topic of the current blog: dark green leafy vegetables and their tremendous
benefits.
When
one enters the supermarket, the physical set-up of each store is virtually the
same with the fresh produce section offering a vast array of colors, aromas,
and variety. Unfortunately, most individuals stray away from the diverse
selection of produce due to their obscure, unheard of names or the limited knowledge
on how to prepare the food. Even though I am an individual in the field of
nutrition, I am no stranger to the above scenario; however, I do know the
importance of incorporating a variety of fruits and vegetables into the diet.
One major group of food items overlooked by many people, including myself, are
the dark green leafy vegetables including kale, mustard greens, dandelion
greens, and collard greens. Depending on the grocery store, one may be lucky enough
to have a great assortment of green leafy vegetables but may feel inundated by
the number of choices. Thus, he or she may reroute his or her selection to the
more typical American variety, including bell peppers, broccoli, green beans,
and carrots to name a few. Although these are great choices, we may not be
getting the best bang for our buck when considering nutrient content.
It is well established that increasing fruits
and vegetables in one’s diet reduces the incidence of disease, such as obesity,
cardiovascular disease, cancer, and diabetes. Moreover, the consumption of a
specific subset of foods, including dark green leafy vegetables, may provide
additional benefits in disease prevention compared to the traditional fruits
and vegetables1. The specific reasons for the
potential added protection from disease with increased consumption of dark
green leafy vegetables is currently unknown. Although nutrients such as vitamin
C and E are prevalent in varying concentrations across a number of fruits and
vegetables, the phytonutrient composition can differ quite drastically.
Phytonutrients are components of plant material that are not required to
sustain life (such as our requirement for vitamins and minerals) but may have
beneficial effects for preventing disease. Interestingly, most phytonutrients
produced by plants act as part of their “immune system” to prevent their
destruction by the environment, such as ultraviolet radiation (UV light) and
pests. Due to diverse growing environments, the phytonutrients in plants can
vary drastically. This has lead researchers on the quest to discover what
chemical components in plants can provide optimal health for humans. Remarkably,
the traditional diet from a society in Southern Japan exemplifies the importance
of a diet high in phytonutrients, especially from dark green leafy vegetables.
Okinawa
is the southernmost prefecture of Japan and has the highest number of centenarians
(individuals over the age of 100). One of the main reasons attributed to the
high life expectancy of Okinawans is due to the structure of their diet2.
With this notion, scientists have flocked to this region to learn what components
of the Okinawan diet promote longevity. Specifically, a major component of
their diet includes dark green leafy vegetables, such as seaweed (although I
don’t know if I would necessarily want to eat it). As would be expected with a
longer life expectancy, these individuals also have reduced incidences of
disease such as coronary heart disease and colon, prostate, and breast cancer
when compared to the United States. Although there are many other environmental
influences that may promote the longevity in Okinawans, it provides an
excellent example of how one’s diet significantly influences a healthy
lifestyle.
One of the next questions that may be running
through your mind is, “how can I get mega doses of these phytonutrients so that
I can live a healthier life.” Although I have a strong opinion about
supplementation (which I will most likely cover in a later blog) the answer may
not be a single or handful of phytonutrients. Interestingly, it is predicted
that there are thousands of phytonutrients within a given plant and the
interaction among phytonutrients may be required for any health benefit. Therefore,
it would simply be easier to consume the plant product instead of relying on a mega
dose of one or two phytonutrients.
My
recommendation for you then is to try and step outside the box and try a
variety of different dark green leafy vegetables such as the ones I listed
above. One of the best aspects of these vegetables is they are fairly inexpensive
as you can get a pound, which is plenty for a few servings, for under a couple
of dollars. One of the recipes that I found I like is provided below. It is a
simple and quick way to prepare a kale, which is one of the most nutrient rich green
leafy vegetables around.
Although some of the green leafy
vegetables may be extremely tough to eat, you may want to try them raw (after
they have been washed thoroughly) to see if you prefer them this way. If not,
steaming is always a great way to soften the texture. My wife found this recipe
for steamed kale that we tried a few nights ago.
Please
feel free to share any recipes you find and enjoy so that others can try them
out. Also, let us know what types of dark leafy greens you try and provide any
recommendations or insight you gain from testing them out.
Lastly,
please post your comments and don’t hesitate to ask any questions. I may not be
able to provide you with the most complete answer but I will try my best. Also,
please list any topics that you would like covered in the next blog. I have a
running list of ideas but want to take all of your questions and interests into
consideration. If no one provides an idea, I was going to cover “the beneficial
and detrimental impact of carbohydrates on health” for the next blog. Also, I
am planning on trying to make this a weekly or biweekly event as I have more
time to devote to the blog.
References
1. Johnston, C.S., et al. (2000) More Americans are eating "5 a day" but
intakes of dark green and cruciferous vegetables remain low. J Nutr 130, 3063-3067
2. Willcox, D.C., et al. (2009) The Okinawan diet: health implications of a
low-calorie, nutrient-dense, antioxidant-rich dietary pattern low in glycemic
load. J Am Coll Nutr 28 Suppl,
500S-516S
