Whether you’re a seasoned athlete or running your first marathon, blood biomarker testing can offer crucial insights about your nutritional deficiencies, performance and overall health.

Markers such as Vitamin D, Iron, Magnesium, Testosterone, Cortisol, Creatine Kinase, HS-CRP and Lipids are great for assessing nutritional deficiencies, chronic stress and inflammation, muscle/tendon injury risk, as well as overall health risks. In this article we focus on nutritional deficiencies that are common among athletes, and that can typically be uncovered through a blood biomarker test. But first, let’s look at the signs.

The Symptoms

Having a well balanced diet is not just desirable but critical for anyone looking to stay healthy and perform well. One the of most common signs of nutritional deficiencies is reduced energy and increased perception of effort in training. As an athlete, you may feel like that you need longer to recover between sessions. This can be obviously detrimental, but luckily it’s also something that can easily be tackled.

1- Vitamin D

Why it matters:

Vitamin D is associated with bone and teeth health, muscle strength and mass, and healthy immune function. It has been shown that even small deficiencies in Vitamin D can impede athlete performance.

What to do about it:

Very few foods naturally have vitamin D. Fortified foods provide most of the vitamin D in American diets: Fatty fish such as salmon, tuna, and mackerel are among the best sources. Beef liver, cheese, and egg yolks provide small amounts. Mushrooms provide some vitamin D. Sun exposure and supplements will help you get Vitamin D as well.

2- Iron

Why it matters:

As Alex Hutchinson explains iron is “a key component of hemoglobin, the protein in red blood cells that ferries oxygen from your lungs to your muscles. If you’re short on iron, you risk starving your muscles of oxygen. It doesn’t get any more important than that.”

The standard estimate is that 3 to 11 percent of male athletes and 15 to 35 percent of female athletes have some form of iron deficiency.

What to do about it:

Common foods that can help include red meat, liver, dark green leafy vegetables, fortified cereals, beans, nuts and dried fruit. Vitamin C also aids your absorption of iron. Supplements also help, of course. However, athletes should be careful not to fall into over-supplementation, which can be detrimental as well. A simple blood biomarker test can help you understand where you stand.

3- Magnesium

Why it matters:

Magnesium is a mineral that's crucial to the body's function. It helps keep blood pressure normal and the heart rhythm steady. Magnesium also plays an important role in bone health.

What to do about it:

Make sure you include the following foods in your diet: Green leafy vegetables, nuts, fish, meat, dairy, brown rice and whole wheat bread. Most people can get more than enough magnesium from foods and do not need to take magnesium supplements. Excessive use of magnesium supplements can be toxic, so make sure you know your levels before you start taking supplements.

4- B12

Why it matters:

Vitamin B12 has many roles in your body. It supports the normal function of your nerve cells and is needed for red blood cell formation and DNA synthesis.

What to do about it:

Vitamin B12, also known as cobalamin, is an essential vitamin that your body needs but cannot produce. It’s found naturally in animal products, but also added to certain foods and available as an oral supplement or injection.

5- Zinc

Why it matters:

Zinc, a nutrient found throughout the body, helps your immune system and metabolism function. Zinc is also important to wound healing and your sense of taste and smell.

What to do about it:

With a varied diet, your body usually gets enough zinc. Food sources of zinc include chicken, red meat and fortified breakfast cereals. The recommended daily amount of zinc is 8 milligrams (mg) for women and 11 mg for adult men.