Fall foliage 2013 2

One answer is very simple: antioxidants. Xanthophylls and carotenoids are two types of antioxidants found in fruits, vegetables, and fall foliage.

Regarding fruits and vegetables, xanthophylls are yellow plant pigments found in these foods and leafy greens. Well-known xanthophylls include lutein and zeaxanthin which have been studied for potential benefits in human vision. Carotenoids are orange plant pigments found in some leafy greens and orange fruits and vegetables. Well-known carotenoids include beta carotene and alpha carotene.

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Regarding leaves on trees, xanthophylls and carotenoids are present in leaves for the entire life cycle and are only revealed when chlorophyll production ceases toward the end of this cycle, which happens on a large scale in the fall. Chlorophyll is a green pigment that plays a role in creating energy for green plants from sunlight through a process called photosynthesis. Chlorophyll breaks down with exposure to sunlight throughout the life cycle of leaves and therefore constantly has to be replaced. As autumn approaches and a leaf approaches the end of its life, chlorophyll is no longer replaced by the plant, revealing the xanthophylls and/or carotenoids underneath.

Easton, October 28 2012 3

In addition to yellow and orange pigments, we see red pigments called anthocyanins in some fall foliage. Other anthocyanins are purple and blue in color and are found in blueberries, raspberries, and blackberries. In contrast to xanthophylls and carotenoids, anthocyanins are not present throughout the life of the leaf, but instead are made at the end of the life cycle when chlorophyll production ceases. Not all leaves contain anthocyanins.

Blackberries, blueberries, and raspberries

To summarize, xanthophylls, carotenoids, and anthocyanins are groups of antioxidants found in both fall foliage and fruits and vegetables. All three types of phytonutrients help protect the leaves of trees from stresses such as constant sun exposure which can generate free radicals. This is especially true for xanthophylls and carotenoids as they are present for the entire life cycle of the leaf. Similarly, the xanthophylls, carotenoids, and anthocyanins we eat from fruits and vegetables are thought to help protect our internal tissues from the free radicals to which they are exposed.

What about the brown pigment seen in some fall foliage? This pigment is called tannin and is revealed when chlorophyll, xanthophylls, carotenoids, and anthocyanins break down near the end of the leaf life cycle.

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Ah, the holidays! Ever since I was a young girl I looked forward to the month of December for its festivities and time spent with family and friends. When I started on my raw food journey in 1990, I designed raw alternatives of my favorite holiday dishes and desserts to share with my loved ones. I included one of my recipes in an earlier blog post – butternut squash pudding, which has become a new holiday tradition in my family.

Spices that are often used in holiday recipes have been studied for their antioxidant content. The antioxidant activity of the compounds found in spices and foods has been measured using a system called ORAC, or oxygen radical absorbance capacity. An ORAC value of a food is a measurement of the ability of antioxidants in the food to neutralize free radicals in vitro (in a test tube or laboratory). The ORAC measurement has been questioned by members of the scientific community because it is measured in vitro and not in living organisms (in vivo). A free radical is a molecule with an unpaired electron that can cause damage to cells in our body.

Much is currently known about nutrition, and there is much that we have yet to learn. Our scientific, clinical, and experiential knowledge about nutrition is incomplete and will continue to increase as our inquiry in this area progresses. I personally would be interested to see the ORAC values of foods measured in humans and other living beings (in vivo). Hopefully this information will be available sometime in the future.

Here is a sampling of holiday spices and their respective ORAC values:

Total ORAC value (µmol TE/100 g)
Cinnamon, ground 131,420
Cloves, ground 290,283
Ginger, ground 39,041
Nutmeg, ground 69,640

I was amazed to see the high ORAC value of these spices, especially when compared to popular high ORAC value foods, such as:

Blackberries 5,905
Blueberries 4,669
Wild blueberries 9,621
Raspberries 5,065

 

Bueberries, raspberries, and blackberries

One might think, based on this information, that cinnamon, cloves, ginger, and nutmeg are superior sources of antioxidant activity to the fruits stated above. The spices are superior, PER 100 GRAMS. Please note that ORAC values for foods are reported per 100 grams.

But how much of each of these spices do we actually consume in a serving? Let’s do some simple calculations using ground cloves as an example. A typical 9” round pumpkin pie recipe calls for ¼ teaspoon of ground cloves. ¼ teaspoon of ground cloves weighs approximately 1 gram. The ORAC value for 100 grams of ground cloves is 290,283. If we divide this number by 100, we get a value of almost 2903 for 1 g of ground cloves in a whole pumpkin pie.

Now, there are generally 8 pieces in an average pumpkin pie. So, if we divide 2903 by 8 we get a value of about 363 for the 0.125 grams of ground cloves in one piece of pumpkin pie. Given that ORAC values are tested and reported per 100 grams of food, I cannot say that 363 is THE ORAC value for the 0.125 grams of ground cloves found in the piece of pie. I would need actual studies to confirm or deny this number, since other possible contributory factors must be taken into account. The bottom line here is that one needs to consider nutritional information, such as ORAC values, in the context of the amounts that one actually eats.

For comparison with another type of food, let’s consider the ORAC value and the amount of blackberries in one serving. The ORAC value for 100 g of blackberries is 5,905. One cup of blackberries weighs 144 g, so the ORAC value for 100 g of blackberries is very roughly equivalent to ⅔ of a cup, which could be considered a small serving of blackberries. Whenever I eat blackberries, I usually eat more than ⅔ cup, as do many raw food enthusiasts that I know.

Looking at the actual serving sizes of ground cloves and blackberries, one can strongly question the ORAC superiority of ground cloves to blackberries, or any of the other fruits shown in the table above. Of course, we would need more information on the antioxidant activity in the amount of cloves found in a piece of pumpkin pie to make a more definitive statement.

I would love to see researchers take into account such information when doing their studies, since this would make their information more meaningful and applicable to daily life. In the meantime, we must employ our skills of critical thinking when we hear such pieces of information out of context. Critical thinking is essential in many aspects of life, including the realm of nutrition information. We will address critical thinking in future blog posts.

For those of you interested in delving more deeply into this subject, here are some interesting points to note:

  1. The ORAC values reported are for dried and ground spices. I am curious to know if/how the ORAC value would differ in the fresh versions of these spices, especially ginger, since it is a naturally water-rich root.
  2. ORAC values are measured by weight, per 100 grams. I would like to see an ORAC value comparison per calorie, and as stated earlier, per serving size.
  3. If the food in question is part of a recipe or processed food, what other ingredients and/or processing methods can affect the ORAC value of that food?

For more information on the ORAC values of various foods, please visit: USDA nutrient database and USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 – May 2010

Best wishes for a happy and healthy new year!

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