How blueberries simulate the genetic beneficial longevity effects of caloric restriction - new study

November 27, 2:23 PMSacramento Nutrition ExaminerAnne Hart

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Blueberries

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Latest scientific studies on how nutrition influences longevity genes currently focuses on a plant extract related to resveratrol called pterostilbene, pronounced terro-STILL-bean. Basically, pterostilbene is extracted from blueberries, grapes, and also the bark of a tree that grows in India called the Kino.

How the scientists discovered this plant extract is by examining Ayurvedic medicine, the folkloric medical treatments used in India based on plant extracts. The purpose of looking at these plant extracts is that when tested on animals such as mice, the blueberry and grape extracts used in laboratories appears to make the mice live longer by switching on their longevity gene tags in such a way that it imitates caloric restriction. Most veterinarians know that by restricting calories, but not essential nutrients/nutrition, animals live longer when they eat better while eating less.

If you look at pterostilbene and resveratrol, you'll notice that both compounds have similar structures. They have similar, but not exactly the same functions. But when you combine pterostilbene with resveratrol, the both together work exceptionally well to simulate certain beneficial conditions produced by caloric restriction. Remember that caloric restriction is not fasting or starving. The person or animal gets the essential nutrition with fewer calories.

What scientists found was that pterostilbene and resveratrol taken together or combined in one supplement translate into more benefits that by taking resveratrol by itself. You can check out all the scientific studies listed at the end of the latest article in the Special Winter Edition of Life Extension Magazine (2009), "The 'Other' Resveratrol: A Novel Method to Simulate the Genetic Effects of Caloric Restriction," by Tiesha D. Johnson, RN, BSN.

According to that article, "resveratrol activates genes close the the beginning of the molecular cascade precipiated by caloric restriction." This starts as an 'upstream' action. What happens next is that the activated genes using the pterostilbene then continue to activate numerous disease-preventing genes in a 'downstream' process from the sites connected with resveratrol's upstream action. So as resveratrol works in an upstream action, pterostilbene works the genes in a downstream action.

Pterostilbene amplifies and complements resveratrol's ablity to help turn off those 'epigenetic' gene tags that switch off the cancer and diabetes causing gene tags and switch on the longevity gene tags that support healthy blood fats (lipids).

It's all happening during the normal cycle of gene expression. Basically, the pterostilbene, made from blueberry and/or grape extracts, mimics the beneficial effects of calorie restriction at the molecular level. The idea, scientists report, is that caloric restriction is supposed to suppress cancer development, according to studies.

Calorie restruction changes your gene expression all over the metabolic process. What the plant extracts do is increase activity of fat-sensing complexes that lower blood fats and sugar levels. Basically, scientists are using plant extracts from fruits for chemoprevention. Is it the antioxidants in resveratrol or the anti-inflammatory actions in pterostilbene?

If you look at both resveratrol and pterostilbene, both are called stillbenes. They've been used for hundreds of years in India as folkoric cures for illness in Ayurvedic medicine that is now being studied by Western scientists to see how these plant extracts change gene expression.

The extracts are being tested to see which are good for helping to prevent cancer, lower cholesterol, enhance insulin sensitivity, or increase life span of humans and/or animals. These plant extracts mimic caloric restriction at your molecular level.

The way these plant extracts work is by mimicking caloric restriction. Resveratrol and pterostilbene both act at different locations in the body to control gene expression. They complement each other. Can they increase the quantity of life or the quality of life?

Basically, if you eat a cup of blueberries, you get 20mcg of pterostilbene. Yes, even at that level, the blueberries provide some benefits. But how much more pterostilbene do you need? What is a safe level? A dose of 3 mg daily of pterostilbene in a supplement provides the equivalent of 140 cups of blueberries daily. No one eats like that. So should you take a supplement with pterostilbene or resveratrol combined with pterostilbene? How much is science and how much is marketing?

You only need a small dose of pterostilbene. So in various supplements, it is being added to resveratrol and other supplements. You will probably want to read more about the studies. For further information, you can see the March, 2008 article at BMC Medical Genemics, 20;1:7. See, "Identification of molecular pathways affected by pterostilbene, a natural dimethylether analog of resveratrol." 

The conclusion of this new study, reported that, "Using transcript profiling, we have identified the cellular pathways targeted by pterostilbene, an analog of resveratrol. The observed response in lipid metabolism genes is consistent with its known hypolipidemic properties, and the induction of mitochondrial genes is consistent with its demonstrated role in apoptosis in human cancer cell lines. Furthermore, our data show that pterostilbene has a significant effect on methionine metabolism, a previously unreported effect for this compound."

That 2008 study, "Identification of molecular pathways affected by pterostilbene, a natural dimethylether analog of resveratrol." also reported the following: "Pterostilbene is a naturally-occurring phytoalexin identified in several plant species. It belongs to a group of phenolic compounds known as stilbenes, and is found in the heartwood of sandalwood (Pterocarpus santalinus) [1] and P. marsupium [2].

" It was also identified in the leaves of Vitis vinifera [3], in infected grape berries of var. Chardonnay and Gamay [4], and in healthy and immature berries of var. Pinot Noir and Gamay [5]. Pterostilbene has also been found in berries of some Vacciunium species [5]. Pterostilbene, one of the most extensively studied secondary metabolites found in grapes and wine, is a dimethylether analog of resveratrol that is well known for its hypolipidemic activity. A considerable amount of research effort has been expended to address the biochemical and physiological effects of pterostilbene in animal and microbial systems.

"For example, the antioxidative activity of pterostilbene was first demonstrated in vitro by its inhibition of methyl linoleate oxidation [6]. Pterostilbene was reported to scavenge 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radicals and to inhibit the oxidation of citronellal, and lipid peroxidation in rat liver microsomes and in cultured human fibroblasts [7].

"Pterostilbene isolated from Anogeissus acuminata (Family Combretaceae) is cytotoxic against a number of cancer cell lines, including human breast cancer and murine lymphoid neoplasma cells [8,9]. More recently, it has been demonstrated that pterostilbene can reduce cholesterol levels in vivo in hamsters through the activation of the peroxisome proliferator-activated receptor α (PPARα) [10]. Pterostilbene has been reported to reduce glucose and increase plasma insulin levels significantly in normal and diabetic rats [11]. Furthermore, pterostilbene has been shown to be cancer-chemopreventive [8,12] and anti-inflammatory [13]."

For further information on the healthful benefits of blueberries, see my other Examiner articles, "Does an alkaline diet with added blueberries increase your bone density?" and regarding resveratrol, see, "How to find reliable information on resveratrol."

Resources and References for the 2008 Study,  "Identification of molecular pathways affected by pterostilbene, a natural dimethylether analog of resveratrol." 

Sehadri R: Polyphenols of Pterocarpus and Dalbergia woods.

Phytochemistry 1972, 11:881-898. Publisher Full Text

totext() Maurya R, Ray AB, Duah FK, Slatkin DJ, Schiff PL Jr: Constituents of Pterocarpus marsupium.

Langcake P, Cornford CA, Pryce RJ: Identification of pterostilbene as a phytoalexin from Vitis vinifera leaves.

Phytochemistry 1979, 18:1025-1027. Publisher Full Text

totext() Adrian M, Jeandet P, Douillet-Breuil AC, Tesson L, Bessis R: Stilbene content of mature Vitis vinifera berries in response to UV-C elicitation.