The secret of blueberries: It’s the dephinidins

We continually hear about the benefits of fruits and vegetables for better health. There are a number of them. One is obviously their lower glycemic load that reduces insulin secretion. Another is their polyphenol content that gives fruits and vegetables their colors. Although virtually no research was conducted on polyphenols before 1995, since that time there has been a explosion of animal studies that have indicated their remarkable benefits as anti-oxidants and anti-inflammatory agents.

Upon deeper inspection, there is one group of polyphenols that seems to generate the most consistent health benefits. These are the delphinidins. Delphinidins are a subgroup of a family of polyphenols known as anthocyanidins. To make the story about delphinidins more intriguing, they are primarily found in blueberries. More specifically, the primary sources of delphinidins are the American blueberry, the Russian blueberry (i.e. bilberry), and the Patagonian blueberry (i.e. maqui berry). This is why the published clinical studies in humans seem to consistently involve blueberries. And the clinical data is impressive. Whether it is about reducing oxidized cholesterol or improving insulin resistance in patients with metabolic syndrome (1,2) or improving memory in patients with early dementia (3), the human data on the use of blueberries simply jumps out at you.

Since the active ingredient in each of these varieties of blueberries appears to be the delphinidins, then it is reasonable that the higher the levels of this particular polyphenol, the better the potential results. The Russian blueberry contains six times more delphinidins than American blueberries, and the Patagonia blueberry contains 14 times more delphinidins than the American blueberry. This probably reflects the harsher growing climates that other forms of blueberries are exposed to when compared to the American blueberry, which has become overly domesticated (making it richer in fructose and lower in delphinidins).

However, as with all natural products you have to take a therapeutic dose to get a therapeutic effect. You could measure this therapeutic threshold in terms of their anti-oxidative potential (measured in ORAC units) or the actual amounts of delphinidins themselves. It appears that for a blueberry extract to be effective requires that it provides at least 16,000 ORAC units per day. To put this in perspective, this level of ORAC units is equivalent to eating greater than 20-30 servings of vegetables on a daily basis.

But if the delphinidins are so important for the benefits of blueberries, isn’t it possible that the smaller amounts of the maqui berry might be even more beneficial because of its higher delphinidin concentration? That’s why we have several ongoing clinical trials to explore that potential. I will keep you informed as the results start coming in. Yet in the meantime, keep eating lots of those colorful carbohydrates just like your grandmother told you to eat.

1. Stull AJ, Cash KC, Johnson WD, Champagne CM, and Cefalu WT. “Bioactives in blueberries improve insulin sensitivity in obese, insulin-resistant men and women.” J Nutr 140: 1764-1768 (2010)
2. Basu A, Du M, Leyva MJ, Sanchez K, Betts NM, Wu M, Aston CE, and Lyons TJ. “Blueberries decrease cardiovascular risk factors in obese men and women with metabolic syndrome.” J Nutr 140: 1582 1588 (2010)
3. Krikorian R, Shidler MD, Nash TA, Kalt W, Vinqivst-Tymchuk R, Shukitt-Hale R, and Joseph JA. “Blueberry supplementation improves memory in older adults.” J Agric Food Chem 58: 3996-4000 (2010)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

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This entry was posted in Zone Health and tagged , , , by Dr. Barry Sears. Bookmark the permalink.

About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.

23 thoughts on “The secret of blueberries: It’s the dephinidins

  1. I’ve read that one explanation for the benefits of polyphenols is via hormesis. If that is true, is there harm in taking too much?

    It’s interesting that different polyphenols seem to cause different responses from our bodies in spite of the fact that I think they serve the same function for plant life across the board?

  2. I personally believe that much of anti-inflammatory action of polyphenols may lie with their interactions with gut flora to reduce the potential inflammatory burden on the overall system. This is why I believe it is exceedingly difficult to take too much. Furthermore, animals studies in which therapeutic benefits are observed when translated to man at mg/kg level would suggest that we are still taking far too few of these polyphenols.

    Polyphenols are truly mutli-functional acting as anti-oxidants, anti-inflammatories, and immune-stimulating agents. All will have anti-oxidant activities, fewer anti-inflammatory action, and still fewer as immune-stimulating agents.

  3. Barry, that is an interesting point regarding consuming too many anti-oxidants, Is there any evidence that consuming large quantities of anti-oxidants can reduce the important free radicals in our digestive, breathing and immune functions, what is the ORAC value of your Seahealth product again, it used to be listed on your site, is it 16,000 per serving ???
    Also what do you think of this brown sea weed anti-oxidant below:
    The super-antioxidant found under the sea “This little-known antioxidant is an extract of compounds found in red and brown sea algae called Ecklonia Cava. Ecklonia Cava grows at a depth of 100 feet off the coast of Korea and Japan. Researchers have named this brown seaweed extract Seanol.”
    any better than yours ?

  4. Sea algae usually contain derivatives of Vitamin E, which are not as powerful as anti-oxidants as are polyphenols. The highest concentration of polyphenols are found in fruits and vegetables. A recent article in the European Heart Journal demonstateed that there is linear relationship between intake of polyphenols and reduction of mortality from heart disease. For every 80 grams of fruits and vegetables (and hence the levels of polyphenols) there was a 4% reduction in death from heart disease. So if you consume about 800 grams (almost 2 pounds per day), there should be an approximate 50% reduction in death from heart disease. Some of the references in that blog have demonstrated that daily intake of 16,000 ORAC units per day have significant benefits on reduction of insulin resistance and oxidized cholesterol.

    • According to Dr. Ray Strand, a respected specialist in nutritional medicine, even though the case for the importance of fruits & vegetables has become more increasingly clear each year and though many of us are committed to making life-style changes which will lower oxidative stress and free-radical damage – the fact remains that a conscientious attempt to consume enough nutrients through our food sources can never be enough. Due to soil depletion and the use of fertilizers, etc. even organic products are woefully lacking in the nutrient content these foods contained 100 yrs. ago. While exercize and a healthy diet should always be maintained no health regimen is complete without the use of a high-quality anti-oxidant supplement.

  5. Dr. Sears,

    There are (at least) 2 major differences in blueberries grown here in the US. There is the smaller, much more concentrated and flavorful ‘low-bush’ berry (Vaccinium angustifolium) grown in the rocky soil here in Maine, and the larger ‘high bush’ berry (Vaccinium corymbosum) grown for instance in New Jersey. I would expect the health properties of these two variants to be quite different. Will you and yours be researching and contrasting the benefits of one over the other?

    • The higher the latitude, the more polyphenols are required to produce to reduce radiation damage. Maine blueberries will have more polyphenols than New Jersey counterparts. The are also smaller being less sugar content. Therefore the polyphenol/sugar ratio will be lower in Maine blueberries. Usually a good rule is the more tart the taste of a fruit, the higher the concentration of polyphenols. This is because they are incredibly bitter compounds. The Maqui berries grow in a much more difficult climate than found in Maine and as a result their production of total polyphenols is much greater and especially in delphindins (actually 13 times greater). We are beginning a number of clinical trials that will be studying the synergistic action of polyphenols from the Macqui berries with OmegaRx in the treatment of brain trauma and metabolic syndrome.

  6. Dr. Sears,

    In light on this new info on blue berries, if we “OD” on them do you consider the benefits of delphinidins warrant increasing glycemic load beyond “Zone” recommendations?

    • The best way to increase delphinidin content is supplementation with the isolated polyphenol fraction in which all of the carbohydrate contents have been removed. Now you get the increased anti-oxidant and anti-inflammatory benefits of the polyphenols without any impact on the glycemic load of the diet.

  7. Do you recommend taking blueberry extract that is available in nutrional stores? They have a much higher concentration of polyphenols than you can obtain by eating a normal amount of fruits/blueberries.

    • Many blueberry extracts are simply dehydrated blueberries meaning they are still rich in sugars. The ideal extracts are those in which the sugars have been removed. These extracts will a very high ORAC rating. This is the type of extracts that you want to use.

  8. We have wild and domesticated saskatoons nearby and in abundance. They grow on shrubs and look similar to a blueberry, but are a wine colour with an almond note in the flavour. I eat them everyday (frozen from my garden) in a smoothie, believing that they might have similar properties to blueberries. But I’d sure like to know if there is any nutritional research on saskatoon berries. Do they also have delphinidins?

    • Having spent time in Saskatoon, I know it is very difficult climate. This climate would encourage greater levels of polyphenol production in native berries. Unfortunately, I don’t have any idea of the delphinidin content of such berries.

  9. Dr. Sears – there’s a minor typo in the title of this piece – “The secret of blueberries: It’s the dephinidins”. It should be “delphinidins”. An “L” is missing. As always, thank you for all the great work and information!


  10. One of the questions I have regarding antioxidant supplementation is the conundrum of high absorption yet sometimes limited bioavailability. For example, a human study on resvertatrol found that while the absorption of a dietary relevant 25-mg oral dose was at least 70% only trace amounts of unchanged resvertarol could be detected in plasma. Most of the oral dose was recovered in urine. However, they opined that accumulation of resveratrol in epithelial cells along the aerodigestive tract may still produce cancer-prevention and other effects. ( As they say, it wasn’t what you eat or supplement with, it is the bodies capacity to absorb and convert nutrients so they are systemically bioactive. We still have very little understanding of these processes and less than 5% of animal studies translate to humans.

    • My personal feeling is that much of the benefits of polyphenols may occur in the GI tract to reduce the production of inflammatory products made by various gut flora. We have 10 times more bacteria in our gut than we have cells in our body. Many of these bacteria can secrete large amounts of inflammatory compounds that increase the overall inflammatory burden on the body. If the polyphenols are reducing bacteria-induced inflammation in the gut, then the immune system becomes less stressed and therefore more efficient. The primary purpose of polyphenols in the plant world is to act as anti-bacterial agents. Whatever the mechanisms of polyphenol action, the greater amounts of polyphenols in our diet the better the health benefits for us.

  11. Dr Sears,
    Perhaps I’m missing something here. How many blueberries do you have to eat to 16,000 ORAC units per day to get a Therapeutic response? Are you advocating that one should not expect a benefit from eating blueberries, since to get a benefit one would end up eating so many berries that the fructose overload would negate any benefit?
    “However, as with all natural products you have to take a therapeutic dose to get a therapeutic effect. You could measure this therapeutic threshold in terms of their anti-oxidative potential (measured in ORAC units) or the actual amounts of delphinidins themselves. It appears that for a blueberry extract to be effective requires that it provides at least 16,000 ORAC units per day. To put this in perspective, this level of ORAC units is equivalent to eating greater than 20-30 servings of vegetables on a daily basis.”

    • The studies that have been conducted with polyphenol extracts remove the sugar and therefore eliminate the potential of fructose overload. That is difficult process and rarely do you find such products because of the cost. Furthermore, most polyphenol products sold in the mass market (like POM) provide a tremendous amounts of carbohydrates for a limited amount of polyphenols. The reason is that purified polyphenols have an incredibly bitter taste and added sugar hides that taste. As an example, unsweetened chocolate is very bitter, yet only 5% of the mass contains cocoa polyphenols. Multiply the bitter taste of unsweetened chocolate by 20 and you get an idea of what purified polyphenols taste like. The use of highly purified polyphenol extracts in a capsule circumvents these problems as you can get about 8,000 ORAC units in a small capsule without the potential of any fructose or glucose overload.

      • I live in Canada and am looking for an equivilant product of polyphenals here. How do I equate the 500mg of say….ACAI Berries to the 8000 ORAC or any other Antioxident tablet?
        Thank You!

  12. i see the delphinidin supplement is finally here. very exciting news!! i look forward to seeing addtional information released concerning the supplement. in the meantime, i’ve ordered myself a few bottles and trust that it will be well worth the continued investment.


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