@elio we took your questions to a Mayo Clinic pharmacist. Here some information that she gathered, much of it from the Natural Medicines Comprehensive Database http://naturaldatabase.therapeuticresearch.com/

"In general, lutein is rated as “likely safe” when taken orally and in proper amounts. Clinical trials have found it safe to take doses of up to 15 mg daily for up to 2 years. Lutein is considered “possibly effective” for treating age-related macular degeneration (AMD) and cataracts, and there is not enough reliable evidence to determine if it is effective for treating eye strain. With regard to reducing the risk of AMD, it is unknown if lutein supplements are as effective as dietary lutein. Studies focused on cataracts suggest that supplements and dietary lutein may both be beneficial.

There is an interaction between lutein and beta-carotene, but it is unpredictable in that beta-carotene may reduce OR increase the amount of lutein available in the body and lutein may reduce OR increase the amount of beta-carotene available.

Beta-carotene is considered “likely safe” for certain conditions, but is not recommended for use in the general population. Even low doses have been associated with increased risk of lung and prostate cancer in people who smoke. In fact, taking 20-30 mg daily may increase the risk of lung cancer by 18 to 28% in smokers (especially those smoking more than 20 cigarettes per day), former smokers, those who have had a history of asbestos exposure, and heavy alcohol drinkers. This risk seems to be specific to beta-carotene as a supplement, not the beta-carotene found in foods. Taking beta-carotene in combination with vitamin C, Vitamin E and zinc may reduce the progression of AMD. It is considered “possibly ineffective” for cataracts.

In general it seems that with any history of smoking, it would be best to avoid beta-carotene supplements and eat foods rich in beta-carotene instead.

Copper in doses up to 10 mg per day appears to be safe and tolerable for adults. Higher doses have been shown to cause liver damage. Zinc inhibits copper absorption and is used in certain patient populations to help the body eliminate excess. If using copper as a supplement in the recommended daily amount (10 mg or less), there should not be a need to also use zinc."

@aliskahan thanks a lot! Are the interactions between lutein and beta-carotene major or minor? Would it be safer to supplement on both in order to avoid any deficiency that might occur in the future? Also, how much zinc, copper, and carotenoids -beta-carotene and lutein- in pumpkin seed oil? Is it okay to take 2 g of pumpkin seed oil daily along with 25000 iU (15 g) of beta-carotene? As I mentioned earlier, I'm a very light smoker (2-3 cigarettes per day, sometimes I do not smoke at all). Is there any possibility a/o evidence that supplementing with beta-carotene will affect my lungs in the long run? Besides, is it safe to take 40 mg of niacin (vitamin B3) which is found in a particular multivitamin along with red yeast rice? I've read that major interactions may occur when daily dosages of >=1 g of niacin are taken daily with 20+ mg of statins. Thanks!

I recommend that you talk to your physician for informed answers about how these supplements may interact for your personal situation, given your lifestyle and medications. Before taking supplements it's always wise to discuss with your primary care provider. If you do speak with your physician, I'd love to hear what you find out.