Antioxidant eye vitamins or eye and age-related macular degeneration (AMD)

What are oxidation, free radicals and anti-oxidants?

Oxidation is a process to convert food into energy (ATP), during which an atom/molecule loses electrons. It may at times produce free radicals, which may set off chain reactions that may damage cells (for a more technical explanation: Being lacking electrons, a free radical is constantly looking for one to stabilize, thus very active).

Antioxidants, having extra electrons, can donate electrons to a free radical to stabilize it (to calm it down) so it will not wreak havoc.

Theory has it that cumulative damage by free radicals may account for many of the degenerative changes of aging and many age-related diseases such as AMD.

This is the basis of using anti-oxidant eye vitamins to treat (not to prevent, though) AMD.

This post is not about AMD, I will simply post this diagram from Harvard Health Letter so you have a rough idea of what is AMD. The prevalence of AMD by age is: age 65-74 (1%); age 75-84 (4.6%); age 85+ (13.1%). I believe the prevalence is much lower for Asian population.

AREDS

A landmark study, the Age-Related Eye Disease Study (AREDS) was reported in October 2001 issue of Archives of Ophthalmology, conducted by National Eye Institute, 4,757 participants for an average of 6.3 years between 1992 and 2001, showing a combination of beta carotene, vitamin D and C and E, zinc and copper can slow or prevent progression in about 25% of those who already have AMD.

Concern was raised as carotene is associated with increased risk of lung cancer in current or former smokers. Zinc dose was lowered as it can cause stomach upset and other side effects.

AREDS2

Several modified regimens were used subsequently in AREDS2 study, using lutein and zeaxanthin to replace carotene, and omega-3 fatty acid was added, the result was reported in 2013: no better and no worse comparing with the AREDS using the original AREDS vitamin cocktail. So the AREDS2 vitamin cocktail also works, as well as, although no better than, the original AREDS regimen.

What are lutein, zeaxanthin and beta-carotene?

Beta-carotene is transformed into vitamin A which is essential to eye health.  Vitamin A is required by the retina to detect the light and convert it to electrical signal.  Lutein and zeaxanthin are the only carotenoids found in the retina of the eye, doing the same job as vitamin A, they can be treated as natural antioxidants. Spinach and kale, lutein-rich vegetables appear to moderately reduce the risk of cataract beside the benefit to AMD.

AREDS2 formula (PreserVision: made by Bausch + Lomb):

Vitamin C 500 mg

Vitamin E 400 IU

Zinc 80 mg (25 mg in the AREDS2 study)

Copper 2 mg

Lutein 10 mg

Zeaxanthin 2 mg

(No beta-carotene)

Do I need to take anti-oxidant eye vitamins?

The other day while at Sam’s Club I picked up a bottle of PreserVision (made by Bausch + Lomb), which is touted as AREDS2 formula.  I am well aware that AREDS showed no benefit from antioxidant vitamins in those who did not already have AMD, in other words, they didn’t prevent one from getting AMD, nor would it improve vision.

Not known to have AMD, why would I need to take antioxidant vitamins? The rationale is that for those who do not see an eye doctor (ophthalmologist) often or regularly, AMD cannot be picked up at its very early stage, taking them, just in case. I mention this to make a point that we all (including myself, a medical doctor) are not doing thing the way it should when it comes to medical care.

There is no substitute to seeing an eye doctor (ophthalmologist). Dr. Jeffrey Heier from Massachusetts Eye and Ear Infirmary said “the exam can determine if you will benefit from vitamins.” Dr. Heier advises against taking anti-oxidant eye vitamins unless one has AMD, although he does encourage eating nutritious diet rich in green, leafy vegetables not only for one's eyes, but for one's overall health.

Ways to protect your eyes from AMD

1. Sunlight thought to possibly promote AMD, wear sunglasses or broad-brimmed hat if necessary.
2. Indulge in fresh fruits and dark-green leafy vegetables, such as spinach, collard greens, kale, they are rich in lutein and zeaxanthin.
3. Smoking can speed up the process of AMD.
4. Consult your eye doctor is the only sure way to find out whether you need to take antioxidant eye vitamins or not.

Kales in our garden: rich in lutein and zeaxanthin

Doctor, do I have to take Vitamin D pill everyday?

There was an article (“Effects of vitamin D supplementation on musculoskeletal health”) recently published on Lancet Diabetes and Endocrinology; it was a meta-analysis report reviewing 81 studies. The conclusion is that normal individuals taking vitamin D supplements doesn't prevent fracture or fall and may increase the risk of kidney stone.

I gave a talk (to a Taiwanese community) on vitamin D some years ago, in which I mentioned the statement of Institute of Medicine (IOM, now called the National Academy of Medicine, is part of the National Academy of Sciences, Engineering, and Medicine) in November 2011.

Vitamin D is still important for bone health, I believe
The following is from the Power Point of my talk. The IOM analyzed more than 1,000 studies and interviewed the experts of various fields and its conclusion “found evidences to be mixed and inconclusive” using vitamin D on various conditions such as cancer, hypertension, cardiovascular diseases, diabetes, metabolic syndrome, immune responses, falls, neuro/psychological functions, physical performance, pre-eclampsia and reproductive function.

Power Point of my talk

But IOM says “current evidence supports vitamin D a role in bone health."  IOM is known to be very conservative, having 10 or more members. American doctors respect, but not necessarily follow its recommendation, Just like Mark Twain says of classic, “a book which people praise and don't read.”

Vitamin D comes with many forms: Those come from foods are D2, skin (with help of sun) D3; both are converted to 25(OH)Vitamin D in liver, then to 1,25(OH)2 Vitamin D in kidney (this is the active form). Level of 25(OH)Vitamin D reflects vitamin D store, so when we check vitamin D level, we measure blood 25(OH)Vitamin D level.

The best source of vitamin D is your skin and sunlight (UVB)

It is the ultraviolet B (UVB) in the sunlight that helps skin make vitamin D, general speaking 10AM to 3PM is the better time to have more UVB. In certain areas such as Boston, there is practically no UVB reaches the earth in winter time (November to February). Skin color also determines the efficiency, fair (white) skin has the best efficiency, the dark skin (containing more melanin) the least effective as the melanin competes for UVB with the vitamin D-making cells. General speaking, it is enough to have 10% of body expose to sunlight for 10 minutes a day for the fair skin.

Of note, vitamin D2 (from food) is only 30% as effective as vitamin D3 (from sun) in maintaining 25(OH)Vitamin D level, that is why we sing “you are my sunshine” with enthusiasm and admiration. Keep in mind, the vitamin D store declines as we age. Ability of vitamin D synthesis from skin also declines with age. We are led to believe that vitamin D deficiency may lead to or accelerate osteoporosis (骨質疏鬆症), even though the Lancet Diabetes and Endocrinology says otherwise.

No consensus for normal blood vitamin D level among professional organizations

The problem comes from the fact that there is no consensus opinion on the normal vitamin D level among various professional organizations.

IOM says the blood vitamin D level is 20 ng/mL or above, but National Osteoporosis Foundation, International Osteoporosis Foundation and American Geriatric Society all say 30-70 or even 30-100 ng/mL. Most physicians go by the “30 to 70 or even 100” normal value.

The best source of vitamin D is your skin and sun; few foods contain vitamin D. Sea shells contain vitamin D, but not all sea foods do (salmon, tuna and mackerel are exceptions) Cheese, egg and yogurt have some vitamin D; this is why we have vitamin D fortified milk, orange juice and cereals.

The following table gives you some idea as to the food sources of vitamin D:

Our body cannot make vitamins, vitamin D is the only exception. Sometime I wonder what is the God's purpose? It is either God knows few of our foods contain vitamin D or vitamin D is more important than any other vitamins.

There is an ongoing vitamin D and Omega-3 trial (VITAL), a large study (more than 25,000 participants) investigating whether vitamin D and omega-3 supplements can lower the risk of cancer, heart disease or stroke; the jury is not out yet.

If one googles Internet, one will find innumerable articles that vitamin D is good for almost all diseases of all organ systems, ranging from cancer to Alzheimer disease, 而且有病治病，無病防身。對於這些報導我是姑且聽之. But for bone health, I go by the normal vitamin D level of 30 ng/mL or above (some say >50 may be detrimental). If one cannot maintain the normal value with one's diet, then vitamin D supplement is the way to go, especially during the winter time.

It is of importance to maintain normal vitamin D level if one has osteoporosis

In case of having osteoporosis, in addition to the specific treatments (bisphosphonates, Prolia, Forteo, Tymlos, Evista, etc.) One needs to strive to maintain normal vitamin D level and to ensure adequate calcium intake.

Power Point of my talk

An article in 2014 British Medical Journal says “People with low vitamin D levels were more likely to die from cancer, heart disease and to suffer from other illnesses.” However, in 2014 the United States Preventive Services a Task Force (USPSTF—a federal government agency) advised doctors not to do “routine” as the benefits of taking vitamin D supplement in a healthy individuals are not proven. 我買了一大瓶 vitamin D 要給 Katy吃，我道她沒有每天認真吃，我也睜一眼 閉一眼。因為我也不確知她到底要不要吃。Some experts warn that taking vitamin D supplement may increase risk of kidney stone or calcification of the blood vessel wall. I believe this may be a concern only for those taking excessive or mega doses of vitamin D.

How much vitamin D supplement one should have everyday?

Institute of Medicine: for those age 1 to 70: 200-600 IU a day; age 71 or above: 400-800 IU a day.

National Osteoporosis Foundation: 800-1000 IU a day.

Endocrine Society (of endocrinologists): 1500-2000 IU a day.

Doctor, do I need to take vitamins every day?

More often than not was I asked this question.  The answer is depending on who you are.  A healthy individual having a well balanced American diet should do fine without taking any vitamins.  This is not to say that vitamins are not needed by anyone or any situation.  Vitamins, like air and water, are essential to maintain normal life process.  Vitamin is called 維他命 in Chinese, which means “maintain his life,” I would say it is 維我命 （maintain my life).

Photo credit to Harvard Health Letter

Vitamin B12, together with folic acid, is required to make blood (red blood cell), lack of which can lead to a condition called pernicious anemia, which is invariably fatal.  Vitamin B12, taken by mouth, needs to bind with a protein called intrinsic factor in the stomach, so that the complex can be transferred to the small intestine to be absorbed.  One with a defect intrinsic factor cannot absorb vitamin B12.   This is why the inevitably fatal pernicious anemia can be easily “cured” by having vitamin B12 injection once a month.

Vitamin B12 is also required to maintain normal nerve and brain function, check blood vitamin B12 level is part of dementia work up.

A pregnant woman lacking folic acid (also called vitamin B9) can have a dire consequence with baby having spina bifida, a serious neurological defect.  It is so crucial that doctors advise the woman to take folic acid before they begin trying to conceive.

If one searches internet one will find vitamin D is good practically good for all organ systems from Alzheimer disease to prevent all sorts of cancers, in addition to bone health.

Speaking of vitamins none are more important than so-called “eye vitamins” which are antioxidant vitamins that include vitamin A, vitamin C, vitamin E, beta-carotene or carotenoids (lutein, zeaxanthin).  There is one credible study showing taking antioxidant vitamins (lutein and zeaxanthin) can slow down the progression of the age-related macular degeneration (AMD or 黃斑變性),

Our body cannot synthesize vitamins (vitamin D made through skin and sun light is the only exception). As is true, like every thing else, the best source of vitamins is from the Nature：The foods we eat.

Let this post serve as an introduction of vitamins, I will make separate post for each vitamin so that I can go into further details, in which I will list the best sources of each vitamin.

There are two main types of vitamins: water soluble and fat soluble.  Water soluble vitamins (all vitamin B: B1, B2, B3, B5, B6, B7, B9, B12 and vitamin C) will be expelled by the body when it doesn’t use whereas fat soluble vitamins (vitamin A, D, E, and K) will be stored in liver and fat tissue when unused, thus a potential for toxicity.

However, not every one can have a well balanced diet or can be sure whether he or she is having a well balanced diet, in which case vitamin supplements will come into play.  While picking up a vitamin bottle from shell, Dr JoAnn Manson, a nutrition guru, recommends the one with a label showing that it has been tested and certified by independent labs such as US Pharmacopeia, Consumer Lab and NSF International.