The argument for and against heavy supplementation vs. tailoring the diet
Athletes, clients, friends and family members often ask me what vitamins and minerals they should be taking in regard to supplementation. This is actually a rather complicated question.
While many would assume it is a good idea to take a multivitamin to fill in the gaps that are missing from their diets, it can also be very harmful if done incorrectly. If you eat a varied diet with whole grains, plenty of calories, protein, fruits and vegetables, you probably do not need a multivitamin, but you might think, “What’s the harm?” In reality, there is a chance you could be putting yourself at risk. With that said, there are some circumstances that do necessitate supplementation.
The harm in excess
It has previously been assumed that the water-soluble vitamins are not harmful in excess because we excrete what we don’t need, and that fat-soluble vitamins are stored in fat cells, so they can be harmful if we get too much. This isn’t exactly true.
We have come to understand that B vitamins and vitamin C, the water-soluble vitamins, can concentrate in our tissues and lead to cancer growth if taken in large amounts. Pyridoxine, or vitamin B6, is stored in the liver and can lead to liver damage if too much is consumed.
Most multivitamins contain exponentially more than 100% of the daily value of water-soluble vitamins because they were previously considered to be safe. More research has demonstrated that this is not the case.
Then there are the fat-soluble vitamins, which include vitamins A, D, E and K. Most of these can cause adverse effects if taken in excess. Vitamin A is also stored in our liver, so too much can lead to liver damage. Vitamin E is an antioxidant, but taking superfluous amounts can disturb the body’s antioxidant system by inhibiting the binding sites for other antioxidants such as vitamin C, copper, zinc and selenium, which serve other purposes.
Vitamin D and synthesis
On the other hand, it is almost impossible to obtain toxic amounts of vitamin D, which we get from sources like the sun, fortified dairy products, fatty fish and shiitake mushrooms. Unfortunately, there are many factors that inhibit the body’s synthesis of vitamin D.
For instance, people who live in the northern latitudes are at a relatively greater risk for vitamin D deficiency because there is diminished exposure to sunlight during the winter months. In the summer when it is easier for us to get vitamin D from the sun, we wear sunscreen.
Additionally, individuals who are overweight sequester vitamin D in fat cells, which renders it unusable by the body. This is a problem because vitamin D plays a major role in regulating inflammation levels. What’s more, vitamin D deficiency is linked with every disease we know of, from asthma, arthritis and cardiovascular disease to cancer and diabetes, just to name a few. Knowing this, vitamin D is the one and only vitamin I recommend to almost everyone. As a dietitian, I typically advise people to get their nutrients from food, but this is one exception to the rule.
Supplementation and critical antioxidants
Let’s move on to the coveted antioxidants, which include vitamins A, C and E as well as copper, zinc, selenium and lutein. Antioxidants are critical because they stabilize the free radicals produced in our body.
While it is important for men to consume antioxidants post-workout, women should avoid them after physical exercise, as they can interfere with the body’s adaptive mechanisms. However, it is still important for everyone to have a high antioxidant intake overall.
Antioxidant food sources include fruits and vegetables, beans, nuts, seeds, shellfish and egg yolks (yes, the yolks, so stop throwing the best part of the egg away). It is essential to obtain antioxidants from your food for a few reasons. First, we haven’t perfected the complicated process of extrapolating antioxidant properties and putting them into supplements. You won’t get the same benefit from a pill, and you may experience harmful effects such as hardening of the arteries. Also, zinc and copper compete for the same binding sites in the body.
People often take zinc to stave off illness, which can inadvertently precipitate a copper deficiency. A copper deficiency inhibits proper use of iron, ultimately causing anemia that is certainly not going to make your running any easier.
Athletes and iron issues
Speaking of iron, I work with a lot of athletes who have issues with iron deficiency, which can cause fatigue, decreased exercise performance, headaches and dizziness. We lose iron in our sweat and from our gastrointestinal tract (that’s right, we poop it out). We also break down red blood cells in our feet when we run. So, we should take iron, right? Not necessarily.
Iron is extremely complicated. It is the opposite of an antioxidant and can actually feed infection. Sometimes we may appear to be iron deficient, but in reality, our bodies are in a state of inflammation. Since iron feeds infection, our bodies secrete a protein called hepcidin to inhibit iron transport and reduce its absorption. That means that while there may be plenty of iron in your body, it is in storage to protect you from more problems.
In addition, if you have your iron measured during an intense training season, your blood volume will be expanded, causing your iron level to appear lower than it really is. If you finish a challenging workout and then get your iron level checked, you may be inflamed, pushing the iron into storage. There are many other blood measurements that you can take before determining if an iron supplement is necessary, including transferrin, ferritin, C-reactive protein (CRP), hemoglobin and hematocrit tests.
These are just a few of the many examples of the negative effects that can occur when we obtain our nutrients from supplementation instead of food. When we eat our nutrients, they can be better absorbed because other nutrients can enhance intake. For example, vitamin C-rich foods such as berries, lemon juice, peppers and tomatoes enhance calcium and iron absorption.
Food preparation and absorption
The way we prepare foods can also affect absorption. Green leafy vegetables such as broccoli and spinach contain calcium and iron; however, those nutrients are poorly absorbed when eaten raw, as they are tightly bound to fibers in the foods like phytates and oxalates that render the calcium and iron non-absorbable.
When cooked, the bind is broken, which allows our bodies to effectively consume the calcium and iron. The other risk is that the calcium and iron that is bound to phytates and oxalates in raw green leafy vegetables can build up and cause kidney stones. When eaten with iron-rich foods, dairy and caffeine can also impair absorption.
The bottom line is that you should eat a varied diet, exercise moderation with all foods and not rely on supplementation to provide you with the nutrients you need. If you have certain conditions such as food allergies, celiac disease, Crohn’s disease or acid reflux, there may be supplements that you require. Those can be determined by working with your doctor or a dietitian.
THERESA DELORENZO, DCN, RD, is the program director for the Master of Science in Nutrition & Human Performance and the Master of Science in Applied Nutrition & Dietetics at Logan University in St. Louis. She is a registered dietitian with 20 years of experience, is the owner and founder of Nutrition for Optimal Performance, and serves as the team dietitian for USA Para Powerlifting at Logan. She can be contacted through nutrition4op.com.
