Quick Hit Summary
Antioxidant supplements, which contain only 1 type of antioxidant (ie- lycopene, etc), are sold in various stores. When looking to buy a specific antioxidant, its important to realize that these phytochemicals seldom work in isolation. Rather, a collection of antioxidants are needed to influence a given physiological process. Although this does not hold true for all antioxidants, studies have shown that when taken in isolation, certain types may actually increase the risk of developing diseases such as cancer. Thus, one should focus on obtaining antioxidants via whole food sources rather than relying SOLELY upon its purified supplement form. To assess which foods have the highest antioxidant content, check out its Total-ORAC score.
Antioxidants
Figure 1. The Beautiful World of Antioxidants7
Antioxidants and their role in human health/performance is not a new topic for the readers of CasePerformance. As seen below, I’ve already written 5 articles covering this topic…
- Understanding Antioxidants, Free Radicals & Oxidative damage
- Dietary Antioxidants: Vitamins E & Athletic Performance/Recovery
- Dietary Antioxidants: Vitamins E & General Health Issues
- Dietary Antioxidants: Vitamin C & Athletic Performance/Recovery
- Dietary Antioxidants: Vitamins C & General Health Issues
Thus far, most of my articles have focused on antioxidant vitamins. However, I’d like to shift our focus a little bit and focus on phytochemicals such as carotenoids and other naturally occurring antioxidants found in whole food sources.
(For reference, phytochemicals refers to chemicals found in plants. Some, but not all, phytochemicals are antioxidants)
Whole Food Antioxidants vs. Isolated Whole Food Antioxidant Supplements
Before I get to deep in this conversation on whole food antioxidants vs. isolated whole food antioxidants supplements, I want to make a distinction. In stating “whole foods” I refer not only to the fruit/vegetable itself but also supplements made with the juice of it (ie- acai berry juice). Additionally, products such as green tea extract which usually consists of the potent antioxidant EGCG along with other phytochemicals naturally found in the plant falls into this grouping. In contrast, isolated whole food antioxidant supplements refers to products that contain only 1 specific phytochemical from a food such as lycopene, lutein, etc.
Fruits and vegetables are a vital part of any healthy diet. This recommendation is made for multiple reasons, including the presence of phytochemicals that serve as antioxidants within the human body. Yes, I realize that this is probably not earth shattering news to any of the highly intelligent readers here at CasePerformance. However, I know many individuals who fail to consume the recommend 5-9 servings of fruits and vegetable per day. Talking with these individuals, I often hear, “ Yeah, I know that I need to include more fruits and vegetables in my diet. However, I take antioxidant supplements that contain lycopene, lutein, resveratrol and quercetin. From what I’ve read, these are the antioxidants that most magazines indicate have protective health benefits. ” So is it true… can taking a few specific antioxidant supplements make up for a diet lacking fruits and vegetables?
Although it would be nice, taking specific antioxidants will not make up for a diet lacking fruits and vegetables. In fact, fruits and vegetables may be a better overall source of antioxidants than “pure” antioxidant supplements. One must remember that nutrients seldom work in isolation. Rather, a collection of chemicals (nutrients, antioxidants, etc) influence a given physiological process in the body. As depicted in figure 2, chemical “X” may convert substance “A” into substance “B”. However, depending on if substance “B” runs into chemical “y” or “z” a positive or negative outcome may occur.
Figure 2 Breakdown of a compound depending on what it comes into contact within a given environment. Figure created by Sean Casey
An Example: Lycopene
Let’s look at lycopene, the phytochemical responsible for the red color of tomatoes. Various studies have shown that tomato based supplements (juice, paste, etc) may have a protective effect on prostate cancer development and progression12. However, I have yet to see any study that has clearly demonstrated that lycopene, when given in isolation, protects against the development/progression of prostate cancer. In fact, recent evidence seems to suggest that when taken in isolation, lycopene may actually increase the risk of developing cancer. This was observed by Talvas et al. who examined the effects of tomatoes and pure lycopene consumption on cancer related prostrate gene expression3. Over the course of 7 weeks, researchers had 30 healthy men (mean age 60) complete the following experimental protocol:
(Except for given supplements/pastes, participants were asked not to consume any lycopene containing foods)
Week 1: Participants consumed yellow tomato paste (~0 mg lycopene) or red tomato paste (~16 mg of lycopene)
Weeks 2-3: Participants consumed no lycopene containing products
Week 4: Participants consumed the opposite type of tomato paste as they did during week 1
Weeks 5-6: Participants consumed no lycopene containing products
Week 7: Participants received either a pure lycopene supplement (16 mg) or a placebo
After each portion of the study, individuals had their blood plasma drawn. This plasma was then incubated with lymph node cancer prostate cells and cancer related gene expression was measured. It was found that consuming red tomato paste significantly reduced the expression of various procarcinogenic genes (ie- cancer causing). Although it wasn’t to the same extent as the red paste, the yellow tomato paste, which lacked lycopene, also appeared to reduce cancer promoting genes, lending credence to the theory that other phytochemicals in tomato products, besides lycopene, influences cancer development. On the flip side of the coin, when individuals were given pure lycopene, it was found that expression of procarcinogenic genes actually increased! Thus, the research team concluded that
“… our data clearly indicate that short-term intake of tomatoes induces changes in the concentrations of serum components that modulate potential cancer-related gene expression… we conclude that lycopene cannot be the sole component responsible for the putative protective role of whole tomatoes… lycopene intake without its matrix [ie – lycopene in its isolated form vs. it as part of a whole food] also led to up-regulation of procarcinogenic genes. Therefore, it can be stated that tomato consumption may be preferable to pure lycopene on the basis of the induction of these procarcinogenic genes.”
Another Example: Beta-carotene
Beta-carotene is another phytochemical with antioxidant capabilities. Early research indicated that consuming fruits and vegetables loaded with high concentrations of beta-carotene was protective against lung cancer4. Thus, it was hypothesized that beta-carotene supplements would protect smokers from developing lung cancer. However, in a meta-analysis conducted by Druesne-Pecollo et al. researchers the opposite was found to be true; individuals who received any supplement containing beta-carotene actually had a 16% HIGHER risk of developing lung or stomach cancer than individuals receiving a placebo5. In the case of lung cancer, these results were found regardless of if the beta-carotene supplement contained a few other antioxidants or if ingested in large doses (20mg/day). If one was exposed to asbestos or smoked, this risk increased by 20%. Likewise, consuming supplements containing 20mg/day vs. placebo increased the risk of developing stomach cancer by 34%. As a side note, this same study also found no effect of beta-carotene supplementation on the following forms of cancer: colorectal, prostrate, pancreatic, and melanoma/non-melanoma skin cancer.
Should I be Concerned if I Take a Supplement Containing Antioxidants?
I know what you’re probably thinking… my daily multi vitamin-mineral complex has “extra” ingredients in it, including beta-carotene and lycopene; should I discontinue taking it? No, you’re probably safe as the doses of these “extras” are usually much smaller than the values mentioned in the above studies. As with all things, moderation is key!
Also, I’m not saying that one is necessarily at an increased risk of developing various chronic diseases if they take antioxidant supplements. Rather, I’m saying that antioxidants seem to work best when they’re consumed in their natural whole food state or as part of a diet containing fruits and vegetables. For instance, results of one study seemed to suggest that 6 months of lycopene supplementation (15 mg/d) would prevent prostrate enlargement and reduce PSA levels (a protein related to prostrate cancer) in men with benign prostrate hyperplasia (BPH)6. These effects were not observed in the placebo group. However, unlike a few of the aforementioned studies examining antioxidants and prostrate cancer, all participants (placebo and lycopene group) in this trial still consumed lycopene containing foods as part of their normal diet. Thus, it appears that the combination of lycopene supplementation AND natural food sources of lycopene (such as tomato products which have other natural antioxidants) had a protective effect rather than lycopene alone.
Obviously there are exceptions to this rule. I’d be out of line to say that a given antioxidant is ineffective if taken in isolation. Good ones do exist. However, it is beyond the scope of this article to touch on those examples in depth. If you’re taking a specific antioxidant in isolation that you heard about via popular press, I encourage you to research it a little bit to make sure it’s supported by science.
That being said, I still recommend consuming antioxidants from whole foods rather than SOLELY relying upon their supplemental form for a couple of reasons. First, as mentioned above, antioxidants seem to work best when they’re found in their natural state, along with all of the other phytochemicals . Second, as seen in the case of beta-carotene, even when a few other antioxidants are included in the supplement, negative outcomes can occur.
Finally, very few antioxidants have been studied to the point where we completely understand the long term implications of supplementing with them in isolation. Keep in mind that most studies showing a positive relationship between a given antioxidant and a health outcome are observational in nature rather than a true experimental study. As discussed in a previous article, observational/epidemiology studies show associations between 2 variables, not true cause and effect relationships. To show true cause and effect relationships, experimental studies must be completed on it.
Figuring out Which Whole Food Source is the Best for You
I’ve emphasized that one should focus on fruits and vegetables as their primary source of antioxidants. The next logical question is, “What fruits and vegetables contain the most antioxidants?” To answer this question, I’d encourage you to look at the ORAC test scores which measures the antioxidant capacity for a given fruit/vegetable product. When looking at this PDF file, look at the Total-ORAC value for each food item.
Although I’m not going to discuss each item, I’d like to point out some general themes that can be observed by examining the ORAC values for various food products. Lets use apples as an example… Each type of apple has a different ORAC value. For instance, the mean Total-ORAC value for red delicious apples is 4275 whereas it’s only 2670 for Golden Delicious. Generally speaking, the deeper/darker the color of a vegetable/fruit skin, the greater it’s antioxidant value. This is why Romaine lettuce or green leaf lettuce has a much higher ORAC score than Iceberg lettuce. Also, the peel of a given vegetable/fruit is loaded with antioxidants. Referring to Red Delicious apples again, its Total-ORAC score drops down to 2936 if the peel is removed. For this reason, fruit or vegetables stripped of their edible peel tend to have lower scores as seen in Figure 3.
Figure 3. Total-ORAC score for select apple products. RD = Red Delicious, GD = Golden Delicious. Figure created by Sean Casey.
On a final note, I must state that the antioxidant content of a given fruit/vegetable is only one variable that should be examined when choosing which foods one should include in their diet. Do not get so caught up in the antioxidant content of a given food that you forget to pay attention to the overall macronutrient and energy content of it!!!
Bottom Line
The effects of antioxidants on general health and well being have been widely publicized by both popular press as well as the scientific community. In response, supplement companies have manufactured various whole food based antioxidants products which contain only a few specific antioxidants such as lycopene, beta-carotene, etc. However, many studies have shown that isolated antioxidant supplements are not as effective as their whole food counterpart with respect to preventing or slowing down the progression of various chronic diseases. Obviously there are exceptions to this rule. Please remember though, antioxidant supplements are just that – a supplement to a healthy diet which should already include 5-9 servings of vegetables and fruit per day. To determine which vegetables/fruits are the best source of antioxidants, I encourage you to check out the ORAC Report.
References
1 Chen L, Stacewicz-Sapuntzakis M, Duncan C, et al. Oxidative DNA damage in prostate cancer patients consuming tomato sauce-based entrees as a whole-food intervention. J Natl Cancer Inst 2001;93:1872–9.
2 Kucuk O, Sarkar FH, Djuric Z, Sakr W, Pollak MN, Khachik F, Banerjee M, Bertram JS, Wood DP Jr. Effects of lycopene supplementation in patients with localized prostate cancer. Exp Biol Med (Maywood). 2002 Nov;227(10):881-5.
3 Talvas J, Caris-Veyrat C, Guy L, Rambeau M, Lyan B, Minet-Quinard R, Lobaccaro JM, Vasson MP, Georgé S, Mazur A, Rock E. Differential effects of lycopene consumed in tomato paste and lycopene in the form of a purified extract on target genes of cancer prostatic cells. Am J Clin Nutr. 2010 Jun;91(6):1716-24. Epub 2010 Apr 14.
4 Wardlaw GM, Hampl SJ, DiSilvestro RA. Perspectives in Nutrition. 6th ed. McGraw Hill. 2004. Page 296
5 Druesne-Pecollo N, Latino-Martel P, Norat T, Barrandon E, Bertrais S, Galan P, Hercberg S. Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials. Int J Cancer. 2010 Jul 1;127(1):172-84.
6 Schwarz S, Obermüller-Jevic UC, Hellmis E, Koch W, Jacobi G, Biesalski HK.Lycopene inhibits disease progression in patients with benign prostate hyperplasia. J Nutr. 2008 Jan;138(1):49-53.
7 Taken by Patrick Feller on August 12, 2009. Accessed Sept 6, 2010 from:http://www.flickr.com/photos/nakrnsm/3815441846/
8 Taken by Stegano on October 26, 2006. Accessed Sept 6, 2010 from: http://commons.wikimedia.org/wiki/File:Small_tomatos.jpg