Start with a good multivitamin. Experts say a multivitamin should act as an insurance policy to make sure you get what you need, but real food contains vitamins, minerals, and nutrients that a manufactured vitamin does not. Eating a healthy and varied diet is your best bet.

Beyond the RDA

RDA levels are established by the Food and Nutrition Board of the National Research Council, National Academy of Science. Dr. Edelberg explains, “You need to go above and beyond the so-called recommended daily allowances (RDAs) if you want to effectively use nutritional supplements to prevent disease and slow aging.” After all, as one doctor explains, the average American gets most of the RDA of vitamins. However, it is not good to be average — the average American will die early of heart disease, stroke, diabetes, or cancer.

These RDA nutrient levels are supposed to prevent deficiency diseases in most healthy people. Unfortunately, the values are criticized for having been heavily influenced not just by science but also by the food industry, economic considerations, and politics.

Vitamin C

Vitamin C is necessary for a healthy immune system, strong connective tissue, and for general good health. If you are not getting enough vitamin C you may be tired, you may bruise easily, and you may just feel generally ill. Dr. Edelberg explains, “Taking vitamin C is a smart preventive move. It’s cheap, safe, and actually works.”

Studies show that vitamin C:

• Improves your immune function, both in preventing and fighting infections

• Protects you from developing heart disease, prevents heart attacks, and stabilizes heart rhythm

• Reduces damage caused by high cholesterol

• Reduces frequency of asthma attacks among asthma-prone patients

• Enhances cancer survival

• Promotes healthy bones

• Statistically, can extend lifespan

Dr. Edelberg recommends taking 1,000 to 6,000 mg daily, with 2,000 mg being a good daily dose. The higher doses are generally recommended for people with specific health conditions. The body can not store vitamin C, so daily consumption is important. If you are adding vitamin C with food, do not overcook, as it can remove vitamins.

Vitamin D

Vitamin D can help protect not only your colon health but also your overall health. A recent article in Archives of Internal Medicine showed that people with low levels of vitamin D had a poorer rate of “all cause mortality” than those with levels in the mid-range of normal.

Because vitamin D is made in the skin when exposed to sunlight, people living in northern states and Canada are at greater risk of vitamin D deficiency. Specifically, higher intakes of vitamin D (1,000–2,000 IU daily) are shown to decrease the incidence of both colorectal and breast cancer. Besides helping prevent the cancer, another study indicates that patients diagnosed with colon cancer who had abundant vitamin D in their blood were less likely to die during a follow-up period than those who were deficient in the vitamin.

Some sun exposure can be valuable as long as you keep it in a reasonable amount. It may be safer and equally effective to take supplements of natural vitamin D. Natural vitamin D is listed as D3 (or cholecalciferol) on labels. This is not the same as the synthetic D2 (ergocalciferol), which is frequently added to foods or commercial dietary supplements. Your doctor can easily measure your vitamin D level with a simple blood test.

Vitamin A

Vitamin A is another important vitamin for good health. It is known to promote healthy surface linings of the eyes, respiratory, urinary, and intestinal tracts. Why do healthy linings matter? If those linings break down, it becomes that much easier for infection-causing bacteria to enter the body. Vitamin A is also useful to aid the skin and mucous membranes, which function as a barrier to bacteria and viruses.

Adults need, on average, about 800 mcg (micrograms) or 5,000 IU of vitamin A per day.

Chronic diarrhea may cause a vitamin A deficiency. A diet that provides five or more servings of fruits and vegetables per day and includes some dark green and leafy vegetables and deep yellow or orange fruits should provide sufficient vitamin A and beta-carotene.

Vitamin A can be found in both animal and plant sources. Animal sources include:

• Pork
• Chicken
• Turkey
• Eggs
• Mozzarella and cheddar cheese
• Egg substitutes

Plant sources of vitamin A include:

• Sweet potatoes
• Carrots
• Broccoli
• Spinach
• Winter squash
• Kale
• Peas
• Sweet red peppers
• Oatmeal
• Tomato juice
• Apricots, fresh and dried
• Peaches
• Apples
• Lemons