In your experience do dietary supplements actually help people, are there more positive effects than negative?
Dietary supplements include vitamin, mineral, herbal and amino acid supplements. Because I am not sure to which you are referring I will respond about each.
It depends on which dietary supplement a person is taking and why they are taking the supplement. If a person decides to take a multi-vitamin supplement that has 100% of the RDA for all vitamins and minerals, it won’t hurt and some people take them thinking they don’t eat a wide variety of foods to give them all the nutrients they need. Unless a person is on a very low-calorie weight loss diet (less than 1,200 calories), most people usually get enough vitamins and minerals over a week to fulfill their body’s needs. Also if you eat over 1,800 calories a day, you easily get all the vitamins and minerals you need due to the amount of food you are eating even when not eating a wide variety of foods groups.
Taking individual vitamin or mineral supplements may not be a good idea especially when not prescribed by your doctor to treat a nutrient deficiency. Some vitamins can be toxic because they are fat soluble (A, D, E, K) so your body stores them, usually in your liver. Some minerals can be irritating to your kidneys when taken to excess (calcium) and form kidney or bladder stones. However, iron supplements may be necessary for people with anemia as they may not be able to eat enough red meat to get their hemoglobin back to normal levels. Hemoglobin carries oxygen around your body inside red blood cells. When iron levels are low, a person feels tired due to lack of oxygen to cells.
The issue is your body evolved to take whole foods, digest eaten food and absorb nutrients to perform various tasks within the body like building and repairing tissue When you take a concentrated source of a nutrient like in a supplement, your body absorbs only about 10% – 15% of that nutrient unless that nutrient is deficient in your body. When you are deficient in a nutrient, your body will absorb more. However, the excess nutrient is excreted in your urine. This can be expensive. Consider that for every $10 you spend on a supplement, only $1 may actually be used by your body. You may be making very expensive urine.
That said, there are some supplements that warrant taking. For instance, vitamin D, calcium, and omega 3 fish oil.
If you live north of a line running east to west from Georgia to Arizona, then you should talk to your doctor about taking vitamin D supplements (1,000 IU per day). Vitamin D comes from sunshine hitting your cholesterol deposits under your skin. It may take only 20 minutes on a sunny summer day to get a good dose of vitamin D. The downside of sunshine is increased the risk of skin cancer. Vitamin D along with calcium and phosphorus helps maintain your bone mass which reduces the risk of broken bones in most people. If you don’t drink milk, eat yogurt or cheese, then you may not be getting enough calcium or phosphorus which are necessary to build bone structure. Then your bone matrix may look like Swiss cheese and not as strong. Weight-bearing exercise also helps maintain a strong bone mass by stressing bones.
Omega 3 fats are in fatty ocean fish like salmon, tuna, mackerel, herring, and sardines. While there are plant sources of omega 3 fats like flaxseed and walnuts which can be changed into omega 3 inside your body, oily fish is the best source. Omega 3 fats make your platelets less sticky and platelets are involved in blood clotting.
Regarding herbal supplements like echinacea for colds. I would suggest talking to your pharmacist about which herbal supplements have published research to prove their effectiveness. Otherwise, you may be wasting your money.
Amino acid supplements are taken by people wanting to increase muscle mass while weight lifting. Unless a person has a higher than normal muscle mass (also a lower than normal body fat), amino acid (protein) supplements are a waste of money. Competitive athletes like football and bodybuilding are two such sports that may require additional protein (up to 1.5 grams of protein per kilogram of body weight) in order to achieve their muscle building goals.
All that said, spending money on real food instead of supplements is the best choice unless your doctor has prescribed a specific vitamin or mineral supplement to treat symptoms you have or based on low blood levels of vitamins or minerals in your blood results.