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eye health

  • In this age of marketing of new fruits of every stripe—“super,” “exotic,” “rainforest,” etc. — it is easy to overlook the fact the best of the fruits for many purposes may be those long known. Bilberry is a good example. Black currant is another. Also called the cassis berry (Ribes nigrum), black currant offers many benefits similar to those found with bilberry and blueberry. Indeed, the list of benefits is quite impressive and includes brain, digestive and eye health along with positive influences in the areas of asthma and overall lung function, colds and flu, and women’s health.

    The black currant is a small shrub standing up to six feet tall. It grows in Europe, European Asia, North America and, as a cultivated crop, is especially well represented in New Zealand. The berry comes in vivid shades of deep red, purple and black. It is quite small, being similar is size to the bilberry, and is similarly nutrient dense. It is particularly high in anthocyanins, which are the purple-black pigments that color the skin of the black currant, giving it its name. Anthocyanins are powerful plant or phyto-antioxidants. In addition to the anthocyanins found primarily in the skin, black currant by way of its seeds is a rich source of both the omega-3 fatty acid alpha-linolenic acid (ALA) and the omega-6 fatty acid gamma-linolenic acid (GLA). The origin of the fruit can have a strong bearing on its nutrient content. New Zealand’s pristine conditions and mineral-rich environment combined with its elevated exposure to ultraviolet light results in black currants that exceed the fruit grown in other areas in terms of anthocyanin content. The protective delphinidin-3-rutinoside constitutes 40 percent of the total anthocyanin content of the New Zealand fruit. Black currant also is a source of proanthocyanidins, compounds more commonly associated with grape seed and pine bark extracts.

    Brain Health
    Today, approximately a third of Americans are over the age of 50 and individuals over the age of eighty-five may make up the fastest growing segment of the population. The “Baby Boom” generation can expect to liver longer than its parents, but with this comes certain challenges. At least nine million Americans currently exhibit sub-clinical cognitive impairment and approximately 14–15 percent of all individuals over the age of sixty-five suffer from some form of age-related dementia.

    Epidemiology studies, including both regional incidence and the analysis of specific risk factors for Alzheimer’s disease, indicate that substantial prevention of the disease in the 50 –70 percent range is a practical possibility for the United States. Brain aging, including conditions such as Alzheimer’s disease, should not be viewed as if it takes place separately from the deterioration of other bodily systems. It long has been established that elevated blood sugar levels, which is to say, diabetes and pre-diabetes, are linked to the rate of various forms of dementia. Glycation, a deleterious form of modification of protein and lipid macromolecules in which a sugar inappropriately binds to the molecules, has been linked to diseases such as diabetes, Alzheimer’s, and Parkinson’s as well as physiological aging more generally. Therefore, controlling weight and preventing blood sugar spikes are candidate courses of action for anyone seriously interested in preventing dementias.

    Although we have grown accustomed to blaming cholesterol for almost any condition, cholesterol is linked to Alzheimer’s disease only when certain contributors to oxidative stress are present. Such findings corroborate the hardly novel observation that only twenty percent of Americans eat the recommended five-a-day fruits and vegetables: it is phytonutrients from the diet that typically control free radical-inducing conditions.

    This is where black currant enters the picture. Certain areas of the brain, such as the areas that involves the neurotransmitter dopamine, are particularly vulnerable to oxidative damage, in part as a result of the neurotransmitter itself. This damage is significant in the manifestation of Alzheimer’s disease and is associated with reduced dopamine levels. Perhaps surprisingly, dopamine inhibits the formation of amyloidbeta peptide fibrils. Researchers have found anthocyanins are powerful protectors against oxidative stressors, with whole fruit extracts more powerful than single fractions. James Joseph of Tufts has been quoted to the effect that black currant is effective in increasing dopamine levels, which are low in Alzheimer’s patients. Dilip Gosh of HortResearch, New Zealand, has performed related research that suggests the ability of brain cells to control calcium concentrations is central to their ability to recover from dopamine cytotoxicity. Animal experiments suggest that anthocyanins taken orally can deliver their benefits centrally, which is to say, to the brain, to protect memory and motor coordination. The polyphenolics in fruits and vegetables, especially those of berries, have been shown to retard and even reverse age-related decrements in motor and cognitive performance.

    Eye Health
    For eye health, the black currant may be even more protective than the bilberry. The bilberry has many historical or traditional uses based upon both the dried berries and the leaves. Used as a medicinal herb since the 16th century, modern interest in the bilberry is partly based on the fruit’s use by British pilots during the Second World War. These pilots noticed that their night vision improved when they ate bilberry jam prior to night bombing raids. In the intervening years, scientists discovered that anthocyanosides, the bioflavonoid complex in bilberries, black currant and a number of other berries, are potent antioxidants.

    Anthocyanosides, i.e., anthocyanins (the name changes based on whether a sugar molecule is attached), provide three primary benefits to the eyes. First, these highly colored plant pigments nourish the retina. Night vision depends on the retina’s ability to constantly regenerate visual purple (rhodopsin), and anthocyanins serve as “building blocks” for this important substance. Tests have confirmed these benefits. When subjects with normal vision supplemented with either black currant or bilberry extract, it was found the acuity of their nighttime vision improved, as did the speed at which they adjusted to darkness and the rate at which they recovered from blinding glare. However, it is important to bear in mind that positive results in trials required the ingestion of 50 mg or more per day of anthocyanins. A prudent level of intake would be on the order of 90 or 100 mg of the anthocyanins per day.

    Another area of benefit involves the inducement of short distance vision and/or its aggravation or exacerbation if already present. Continual close range visual tasking, such as extended viewing of computer screens, leads to the development of tension of the ciliary smooth muscle, which impairs the eye’s refractory adjustment function. One result is axial length elongation, an aspect of myopia or “nearsightedness.” Bilberry extracts may help counter axial length elongation and at least one in vivo test provides evidence black currant is superior to bilberry in this regard. Related to ciliary smooth muscle tension is visual fatigue. As most computer users know well, the fatigue of the eyes can extend to the neck, head, arms, shoulders and lower back. Anthocyanin ingestion may be helpful.

    Several types of deterioration that are typical of aging eyes, such as cataracts and macular degeneration, appear to be influenced by the rate of generation of free radicals. In laboratory trials, changing the diets from commercial laboratory chow to “well-defined” diets rich in flavonoids has shown to be beneficial. Interesting results have been found with human trials in which anthocyanins were supplemented, either alone or in combination with vitamin E.

    Digestive Health
    One of the more unexpected benefits of black currant extract is in the area of digestive health. When researchers at Massey University of New Zealand used an animal model to examine the impact of supplementation of the diet with inulin, 30 percent anthocyanin extract concentrate (BCE) or cassis infused dried fruit (IDF), they found significant results. Desirable bacteria, in this test meaning Bifidobacteria and Lactobacilli, were increased and unwanted gut inhabitants, meaning Bacteriodes and Clostridia, were reduced. Other research has shown black currant may support gastrointestinal health by reducing the activity of â-glucuronidase and increasing that of â-glucosidase.

    Lung Function
    As mentioned already, black currant contains proanthocyanidins as well as anthocyanins and other polyphenolic compounds. Work performed at The Plant and Food Research Institute of New Zealand examined the impact of black currant extract on immune function and aspects of normal inflammatory response when the lungs are challenged. The findings were that black currant supports normal inflammatory and immune responses under challenge conditions. Researchers have suggested black currant extracts may be supportive in conditions such as asthma.

    Colds and Flu
    Elderberry has been used in folk medicine for centuries to treat influenza, colds and sinusitis, and has been reported to have antiviral activity against influenza and herpes simplex. Many people are familiar with these uses. However, relatively few individuals are aware of the fact many anthocyanins are active against viruses. Researchers at the Department of Microbiology, Asahikawa Medical College in Japan looked at the effects of black currant against influenza virus types A and B in vitro. According to the study results, both IVA and IVB were inactivated up to 99.9 percent by 10 ìg/ml of the black currant extract at pH 2.8, and 95 to 98 percent by this concentration at pH 7.2. The growth of IVA in cells treated with 10 and 100 ìg/ ml of the extract after infection was completely suppressed in six hours. The results indicated that the extract was effective under test conditions in inhibiting the release of the virus from infected cells.

    Women’s Health
    Every part of the black currant berry can be used, not just the anthocyanidins and proanthocyanidins found chiefly in the skin. The seed oil is a source of both the omega-3 fatty acid alpha-linolenic acid (ALA) and the omega-6 fatty acid gammalinolenic acid (GLA). GLA is recognized as one of the “good” essential fatty acids used to enhance cell membrane fluidity and function. Although the body can manufacture GLA from dietary linoleic acid, it can be more efficiently utilized for body functions when supplied directly by dietary sources. GLA supports a balanced inflammatory response and has been shown to be important for lung, joint, and eye health. According to authorities such as Andrew Weil, MD, the combination of essential fatty acids found in black currant seeds may influence the production of prostaglandins and assist hormone production to support women during menopause.

    Conclusions
    Black currant has earned its place in the ranks of the “super” fruits. Its range of benefits is similar to that found with bilberry and far better documented than those often asserted rather than demonstrated for acai and other recently promoted fruits. For the health of the brain and eyes, black currant is a winner. It supports normal immune and inflammatory functions. Starting at an intake as low as 50 mg per day of the concentrated anthocyanins, it is compact health insurance against a world of health challenges.

  • Could Chemical Cuisine be the Cause?

    The Eyes Have It
    According to global reports such as the World Health Organization (WHO) blindness and visual impairment project, age-related macular degeneration (ARMD) is the primary cause of visual impairment in industrialized countries, accounting for 19 percent to 30 percent of the total cases of low vision in developed regions. Projected data estimates a 50 percent increase of ARMD prevalence between 2000 and 2020. Evidence now shows there is a definite connection related to chemical components of our foods, lifestyle and eye disorders.

  • According to Traditional Chinese Medicine (TCM), going back more than two millennia, all diseases involving the eye are closely related to liver health, as well as all your internal organs. Taking that into consideration, an imbalance in any of the internal organs may lead to diminishing eye health and eye disease.

  • Eyesight is one of the things that is often taken for granted by most people, until it is too late. Just like other body parts like the heart and the stomach, the eyes also deserve proper care and nutrition. Millions of people around the world suffer from various eye disorders like cataracts (blurred vision, due to the eye lens becoming progressively opaque), and macular degeneration (a deterioration of the macula, the small central portion of the retina). Diet plays an important role in every cell in your body and eye cells are no different. A nutrient-poor diet may lead to eye problems later in life, as well as other complications. It is thus essential to eat the right foods in order to ensure the eyes are protected from damage, and vision loss through age.

    Nutrients for eye health
    Your eyes require specific nutrients to keep them in top condition, and to prevent eye disorders. Antioxidants are usually part of the group of nutrients that maintain the eyes, because they prevent toxic molecules called free-radicals from damaging the delicate tissues of the eye.

    Here Are The Top Nutrients Essential For Eye Health:

    1. Vitamin A
    Also known as retinol in its active form, vitamin A is important in maintaining eye health. It helps the body produce the eye pigment retinoid, which play a significant role in the vision mechanism. Specifically, vitamin A maintains good vision in dim light. A deficiency in vitamin A leads to a condition called night blindness, which renders the affected person unable to see clearly in dimly lit areas.1

    Vitamin A can be found in a variety of food sources. It is particularly high in colored (yellow, orange, and green) fruits and vegetables like squash, carrot, cantaloupe, sweet potato, spinach, broccoli, and other dark green leafy vegetables.

    Processed foods are often fortified with vitamin A to ensure that the consumer gets the recommended daily intake of 700 mcg (adult females) and 900 mcg (adult males), although this form of vitamin A is almost always synthetic (retinyl palmitate or retinyl acetate).

    2. Vitamin C
    Another antioxidant that is important to eye health is vitamin C or ascorbic acid. As an antioxidant, its main function is to prevent free radicals from damaging body tissues. In fact, researchers from the Department of Ophthalmology, at the University of Medical Sciences in Zabjan, Iran, discovered that plasma vitamin C levels is lower in those suffering from cataracts, as opposed to normal individuals.2

    The most common sources of vitamin C are citrus fruits like oranges, lemons, and grapefruit. Non-citrus sources include papaya, strawberries, broccoli, tomatoes, and peppers (green and red). One can also find vitamin C-fortified products in the supermarket like bottled fruit juices.

    3. Lutein and Zeaxanthin
    Lutein and zeaxanthin belong to a group of molecules called carotenoids. They comprise the majority of the carotenoids found in the human eye. Like vitamins A and C, they function as antioxidants and protect the eye by filtering harmful light and preventing glare. A recent study appearing in the journal Ophthalmology, indicated that people with the highest intakes of lutein and zeaxanthin, can experience a 20 percent reduced risk of early age related macular degeneration.3

    These nutrients are not hard to obtain, as they are found in a variety of foods. A study in 1998 by researchers from the Department of Ophthalmology and Visual Sciences, concluded that corn and egg yolk contain the highest percentage of lutein and zeaxanthin, followed by kiwi, grapes, zucchini, orange juice, and spinach.4 The study further recommends that, in order to increase lutein and zeaxanthin levels, colorful fruits and vegetables should be incorporated into one’s diet.

    4. Zinc
    Zinc is a trace element that plays an important role in many body processes. In the eye, zinc works together with vitamin A to produce a substance called melanin that helps protect the eye from damage.5 High levels of zinc are found in the macula of the eye. Deficiency in zinc has been linked to an increased risk of developing macular degeneration,6 which can be easily prevented through proper nutrition. The recommended daily intake for zinc is 11 milligrams for adult males and 8 milligrams for adult females.

    Foods that are rich in zinc include oysters, pork, beef, dairy products like milk and yogurt, whole grains, chickpeas, and lobster. Zinc-fortified foods are also available in the typical supermarket aisle.

    5. Omega-3 fatty acids
    Also known as the “good fats,” omega-3 fatty (DHA and EPA) acids maintain the fluidity and structural integrity of body cells and tissues, and have anti-inflammatory properties. They are also important in proper visual development in infants. In adults, omega-3 fatty acids are important in preventing macular degeneration and subsequent vision loss.7

    The best dietary sources of omega-3 fatty acids are coldwater fish like salmon and mackerel. Tuna is also a good source of omega-3 fatty acids. For vegetarians, algae, flaxseed, hempseed and their oils are the best sources.

    6. Vitamin E
    Vitamin E is a fat-soluble antioxidant that protects cells and tissues from oxidative damage. While more research needs to be done on its importance to eye health, initial studies suggest that vitamin E works together with lutein and zeaxanthin to prevent cataract formation. The American Optometric Association recommends a daily intake of 400 IU of vitamin E to maintain good eye health.

    Dietary sources of vitamin E include sunflower seeds, almonds, wheat germ, vegetable oils, and avocados.

    References

    1. Sarubin Fragaakis A, Thomson C. The Health Professional's Guide to Popular Dietary Supplements Amer Dietetic Assn; 3 edition (November 30, 2006).
    2. Jalal D, et al. Comparative study of plasma ascorbic acid levels in senile cataract patients and in normal individuals. Current Eye Research. 2009 Feb;34(2):118–22.
    3. Wang JJ, et al. Genetic susceptibility, dietary antioxidants, and long-term incidence of age-related macular degeneration in two populations. Ophthalmology. 2014 Mar;121(3):667–75.
    4. Sommerburg O, et al. Fruits and vegetables that are sources for lutein and zeaxanthin: the macular pigment in human eyes. Br J Ophthalmol. 1998 Aug;82(8):907–10.
    5. Ultra-violet and Blue Light Aggravating Macular Degeneration American Macular Degeneration Foundation. https://www.macular.org/ultra-violetand-blue-light.
    6. Smailhodzic D, et al. Zinc supplementation inhibits complement activation in age-related macular degeneration. PLoS One.2014 Nov 13;9(11):e112682.
    7. Lawrenson JG, Evans JR. Omega 3 fatty acids for preventing or slowing the progression of age-related macular degeneration. Cochrane Database System Review. 2015 Apr 9;4:CD010015. [Epub ahead of print]
    8. Head KA. Natural therapies for ocular disorders, part two: cataracts and glaucoma. Alternative Medical Reviews. 2001 Apr;6(2):141–66.