Tag Archives: antioxidants

Eye health essentials; what you need to know about vitamins, minerals and antioxidants

Can what we eat really influence our eyes?

When was the last time you thought about your eyes? You have to admit it; you wake up and they just start working. There is no warming up period, no lag time between opening your eye-lids and receiving images and, unlike your telephone or internet connection, there are no problems with intermittent connections. You eyes just work, day in and day out. In fact you eyes can process around 36,000 bits of information per hour and contribute towards 85% of your total knowledge. Being composed of over two million working parts you eyes use around 65% of all the pathways within the brain. Eyed are truly miraculous structures yet we just expect them to work and never question their existence until something goes wrong. It is with this in mind may be its about time to consider the special nutritional requirements the eyes have. After all, we have discussed heart health in the past and the importance of nutrition and the brain. The eyes have their own specific needs and being aware of this could help offset some of the slow to develop degenerative conditions that afflict a growing number of people. Feeding your eyes may be one of the best dietary and lifestyle changes you could make to help protect such a vital pair of structures.

Eye essentials

It is a sad reality that in some of the poorest countries in the world a simple supplement of vitamin A could prevent the estimated 250 million cases of deficiency that I turn leads on to night blindness and more seriously a drying of the eyes called xerophthalmia. This type of dry eye is not just an irritating symptom it’s a sight threatening condition. In Africa, if you can’t see you will probably not survive very long! Vitamin A is one of those vitamins that acts as a bit of a double edges sword. Too much can cause toxic reactions that may, rather ironically, include dry eyes, along with other serious issues including headache, drowsiness, abdominal pains and vomiting to name a few. Luckily, this is a rare situation since supplements containing vitamin A tend to deliver it in the form of the non-toxic, water soluble form known as beta carotene. True vitamin A (retinol) is a fat soluble vitamin that over time can accumulate in the body to the point where toxicity symptoms may ensue. Beta carotene, on the other hand, is only converted into retinol within the body if the body is deficient in retinol. Unless there is an overt deficiency of vitamin A in its retinol form the water soluble version is always preferable for this reason if you are taking supplements. Simply check the label where you will probably see the vitamin A ingredient described as being in the beta carotene form. Excessive intake of beta carotene can occur especially if supplements containing it are taken at the same time as a regular serving of carrot juice because carrots are also high in beta carotene. Over time the skin can turn a yellow-orange colour, most noticeable on the palms of the hands and soles of the feet. This situation is known as carotenemia and is not in itself hazardous but is a strong indication that you need to cut back on the carrots and beta carotene supplements! In general, it is recommended that people do not take vitamin A (retinol) for extended periods and that pregnant and lactating women avoid it altogether (it can sneak into the diet via fish liver oils and organ meat such as liver) because of the increased risk of damage to the foetus and breast fed newborn. Keeping you intake of water-soluble vitamin A foods up though. These include the bright coloured fruits such as papayas and oranges and the coloured vegetables like sweet peppers, squash and pumpkin. These foods not only deliver water soluble vitamin A but a complex array of other compounds that are being shown to be of great importance in the fight against nutritional related eye problems and offsetting degenerative eye disease. What needs to be remembered here is the fact that the need for vitamin A in African children is quite different from the requirements of vitamin A in the UK population so boosting the vitamin A (retinol form) intake is probably unnecessary and could be hazardous. On the other hand, maintaining vitamin A levels can be achieved by using beta carotene containing supplements if the diet is very low in the foods mentioned above. However, keep the intake to sensible levels to avoid carotenemia!

The antioxidant connection

There does not appear to be a week that passes without some news on the benefits of antioxidants, but what are they and why are they important in maintaining eye health? Antioxidants are naturally occurring compounds that help slow or prevent oxidative changes in the body and oxidative changes are associated with accelerated degenerative disease. We all live in an oxygen rich environment but this comes at a price. As we breathe our cells utilise the oxygen and produce by-products known as free radicals. These are a group of compounds that if left unchecked or are generated at an accelerated rate cause the oxidative damage we all read about. Antioxidants are the key to keeping this process in check since they neutralize and make safe the free radicals. So, the less free radicals there are buzzing around the less damaging oxidative changes occur and, in turn, the rate of tissue damage and degeneration takes place. Hence, diets high in antioxidants have been advocated for a range of degenerative problems ranging from heart disease and diabetes through to arthritis, cancer and eye problems such as macular degeneration. No one would be as bold as to suggest that such diets can reverse these situations but a change in diet and lifestyle can definitely benefit these problems and could slow their progression.

The key antioxidant nutrients are vitamin A (in the carotenoid form), vitamin E and C along with the mineral selenium.  All these important nutrients can be found in a balanced diet but you can top up a diet with a well formulated food supplement. This may be important in those with food intolerances or for those with specific eye related problems where a guaranteed daily intake of antioxidant nutrients would be desirable.

Key antioxidant foods

Vitamin A

Carrots, squashes, broccoli, sweet potatoes, tomatoes, kale, peaches, apricots and all bright coloured fruits and vegetables

Vitamin C

Citrus fruits such as oranges, limes, coloured berries such as blue berries, strawberries, sweet peppers, green leafy vegetables, broccoli

Vitamin E

Nuts, seeds, whole grains, green leafy vegetables, vegetable oils

Selenium

Fish, shellfish, grains, eggs, chicken and garlic

The carotenoid connection

Within the group of antioxidant compounds the carotenoids appear to have specific influence on the health of the eye. One of these, known as lutein, has come to the attention of scientists and had been the centre of intense investigation when it as noted that in may help off set the effects of macular degeneration. Lutein is found in egg yolks and in the dark green leafy vegetables. It appears to act, like all antioxidants, as a free radical neutraliser but because it accumulates in the tissues that are exposed to the outside environment (the eyes and skin) it exerts this effect to great effect in these tissues over other antioxidants that are distributed to all body tissues. In regards to eye health lutein filters out the high energy blue wavelengths common to sunlight and artificial light. By doing this it is thought that lutein could reduce the damaging effects of these wavelengths on light exposed tissues such as the eye and skin. Getting enough lutein (research suggests around 6-10 mg per day) may be difficult from diet alone since you would need to eat a large bowl of fresh spinach every day to get around 6mg. This could be a case where a food supplement is a good idea. Another up and coming eye specific antioxidan is known as zeaxanthin. Again, it belongs to the carotenoid group of compounds.

Foods high in key carotenoids

High lutein foods

Yellow peppers, spinach, mango, bilberries, green leafy vegetables, broccoli, eggs

High zeaxanthin foods

Orange peppers, corn, lettuce (not iceberg), tangerines, spinach, broccoli, oranges and eggs

Pulling it all together

It is clear that good food promotes all aspects of health but certain foods do appear to be associated with specific eye related nutritional needs. A large trail (the Age Related Eye Disease Study trial, see for details) has confirmed the importance of the antioxidants vitamin A, C, E and the minerals selenium, zinc and copper in slowing the progression of age related macular degeneration so we know that boosting those foods high in these nutrients or taking a well formulated supplement is going to be a good idea. A number of smaller studies have also focused on nutrition with special reference to lutein and zeaxanthin. Both of these compounds have been associated with improved eye health.

When looking to the UK population, the Royal National Institute for the Blind comments that research has shown that many people do not get enough vitamins and minerals from their diet and suggest the use of food supplements. These must not be taken, however, as a substitute for a balanced diet!

When to consider a eye specific supplement

  • When intake of fresh fruit and vegetables are low
  • When the absorption of vitamins and minerals poor
  • When its hard to obtain and prepare fresh produce
  • When food intolerances prohibit eating key foods

Product link

Vision Essentials: balanced all-in-one eye specific nutrition

Useful Contacts

Royal National Institute for the Blind

Macular Disease Society

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Antioxidant supplements & artery health – the latest!

Just published… a key study looking at the effect of antioxidant supplementation with vitamin C, vitamin E, coenzyme Q10 and selenium on arterial health and  inflammation. As the research gathers pace, heart disease and the clogging of the arteries known as atherosclerosis is being view more as an inflammatory disease rather than a passive accumulation of fatty material within the walls of blood vessels.

This latest paper helps support the long held theory that antioxidants can help off set this process and protect the health of the cardiovascular system.

In this study, 70 people with two diagnosed cardiovascular risk factors (see the study for details) were recruited from a hypertension clinic. 35 people were given a 6 month course of capsules containing vitamin C (500 mg) vitamin E (200 iu), co- enzyme Q10 (60 mg) and selenium (100 mcg) while the other 35 were given a placebo. The summary conclusion is displayed below and the results and technicalities can be viewed by following the link at the end of this post.

Conclusions: Antioxidant supplementation significantly increased large and small artery elasticity in patients with multiple cardiovascular risk factors. This beneficial vascular effect was associated with an improvement in glucose and lipid metabolism as well as decrease in blood pressure.

The original paper is free to download from the open access journal by clicking here.

Shargorodsky M, Debbi O, Matas, Z, Zimlichman R. Effect of long term treatment with antioxidants (vitamin C, vitamin E, coenzyme Q10 and selenium) on arterial compliance, humoral factors and inflammatory markers in patients with multiple cardiovascular risk factors. Nutrition & Metabolism 2010, 7:55 doi: 10.1186/1743-7075-7-55

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Ask The Pharmacist; August posting

This is our August blog post. The first in our new monthly postings entitled “Ask The Pharmacist“. We invite you to voice common questions that our colleague, Holistic Clinical Pharmacist Dr. Cathy Rosenbaum, can respond to.

Please feel free to contribute and post a comment below or visit Dr Cathy’s blog by clicking here.

This months question:

  • Dietary Supplement Mania.  Should we worry about mega-dosing fat soluble vitamins or water soluble vitamins or all of them?  Why?
Dr Cathy’s reply:

Fat soluble antioxidant vitamins can accumulate in the body over time and cause unwanted side effects. For example, vitamin E in doses higher than 200 IU daily for more than two years can increase risk of stroke and other cardiovascular disease. Vitamin A intake higher than 1250 IU daily (supplement or juicing) increases risk of hip fracture in both men and women. Water soluble vitamins have their issues in high doses, too. Vitamin C may actually be pro-oxidative in doses higher than 500 mg – 1,000 mg daily. It can cause kidney stones, increased risk of bruising and bleeding as well. The body does not absorb more than 250 mg daily.

All three of these supplements are excellent antioxidants but it’s still better to eat colourful fruits and vegetables from the Mediterranean Diet than to supplement since there are literally thousands of antioxidants in nature from which to choose. The body craves variety.

Be sure you talk with your doctor or pharmacist about the best vitamin supplements for your individual health needs and goals.

Be healthy!

Dr. Cathy

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Can vegetables prevent diabetes?

Type-2 diabetes is becoming or will become a real plague… With our increasing life expectancy and increasing body weight as we get older the tendency towards developing late onset problems in regulating our blood sugar metabolism appears to be an inevitable consequence.

However, those in the nutritional world have always advocated a diet rich in fruit and vegetables and low in refined (table sugar, white flour etc…) carbohydrates as a way to ward off this problem. The sad thing is, this type of advice is so run of the mill these days that the true impact of such a simple change often goes without a second thought; everyone knows that we should eat plenty of fruit and veg… so, whats new there?

Well… the latest research can now pot some numbers and ‘science’ behind these claims. In the August issue of the British Medical Journal a feature supporting the role of vegetables in diabetes prevention has hit the media. In a collaboration between the University of Otago in New Zealand and Imperial College in London the findings boost the status of lowly dietary greens. The BMJ’s editorial entitled can specific fruits and vegetables prevent diabetes? clearly points out that; “…an additional one and a half UK portions (roughly 120 g) daily of green leafy vegetables (for example, cabbage, brussel sprouts,broccoli, cauliflower, and spinach) has the potential to reduce the risk of diabetes by 14% independently of any effect of weight loss.” such a dietary change is not difficult to instigate and is good news for all those with a family history or those feeling overwhelmed by the more intensive dietary suggestions commonly promoted for diabetes prevention.

The study does underpin the need for good nutrition. Our modern diets are full and overloaded with excessive calories whilst being low in key nutrients that include trace minerals and antioxidants. Again, this is not a new concept but it appears that before such basic advice is taken seriously someone has to do the science to prove the point and then it hits the headlines (see the BBC news post), almost as some kind of new medical revelation!

For those interested, a full article on the subject of diet and type-2 diabetes prevention entitled Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis can be downloaded by clicking here.

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Vegetable based antioxidant formula

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