Nutrition & sports

The Sports Performance Profile is a bundle of 24 tests designed for people who train regularly—both recreational and competitive athletes—and want more thorough monitoring than a routine checkup. It includes the 9 tests in the Basic Checkup (complete blood count, blood glucose, kidney and liver function, lipid panel, uric acid and complete urinalysis) and adds three sport-focused blocks: sports medicine markers, iron, and a broad micronutrient panel.

The three sports markers are: CK (creatine kinase, or CPK), the most widely used marker for assessing muscle damage; TSH (thyroid-stimulating hormone, or thyrotropin), because thyroid function regulates metabolism and directly affects energy and performance; and high-sensitivity CRP (C-reactive protein), which measures low-grade inflammation and helps interpret other values, such as ferritin, which rises with inflammation.

Ferritin is the most relevant marker in the iron block: it reflects your iron stores and changes well before the complete blood count does. Iron deficiency is the most common nutritional deficiency in endurance sports (running, cycling, triathlon, swimming), especially in women and in people who follow a vegetarian or vegan diet. It shows up as fatigue, poor performance, an elevated resting heart rate and slower recovery; detecting it early makes it possible to correct it before anemia develops.

The micronutrient block includes 25-OH vitamin D, ionized calcium, magnesium, zinc, vitamin A, B vitamins (B1, B6, B12), vitamin C, vitamin E and selenium. Magnesium and calcium play a role in muscle contraction and nerve function. Vitamin D—deficiency of which is very common in Argentina due to low effective sun exposure—is involved in muscle strength, bone health and immune function. Zinc, vitamin A, vitamin C, vitamin E and selenium play a role in immunity and in the body's antioxidant defenses. Supplementing without a deficiency does not improve performance. B vitamins sustain energy metabolism: B1 in the use of carbohydrates, B6 in protein metabolism, and B12 in DNA synthesis, which is needed for red blood cell maturation and the prevention of megaloblastic anemia.

The Sports Performance Profile is not a diagnostic test and does not replace a sports medical evaluation (cardiology checkup, exercise stress test). Its value lies in providing a detailed biochemical snapshot that your doctor or sports nutritionist can use to personalize your training, diet and any supplementation. It is done with a single blood draw, after a 12-hour fast. Avoid intense or unaccustomed workouts (weights, hills, intervals) in the 48 to 72 hours beforehand, and don't come in the week after a marathon or triathlon. Don't come if you have a fever or an infection. Let us know if you take creatine, iron, biotin or other supplements.

It is a laboratory test that measures the proportion of different fatty acids (fats) present in your blood, particularly those in the Omega-3, Omega-6 and Omega-9 groups. Omega-3s (such as EPA and DHA, abundant in fatty fish) and Omega-6s (common in vegetable oils) are considered essential fatty acids: the body cannot make them on its own and depends on what you eat. Omega-9s, by contrast, can be produced by the body.

This profile usually includes the so-called Omega-3 Index, which measures the percentage of EPA plus DHA relative to total fatty acids in red blood cell membranes. This measurement was chosen because red blood cell composition changes little in the short term and reflects tissue status better than a single plasma value. It was proposed in 2004 by researchers William Harris and Clemens von Schacky.

The laboratory may also report the Omega-6/Omega-3 ratio. It's important to understand what these numbers mean: they are indicators of the nutritional status of fats in your body, which a health professional interprets together with your medical history, your diet and other tests.

The main interest in the Omega-3 Index lies in cardiovascular health. Various observational studies have found that people with higher levels of Omega-3s (EPA + DHA) in their red blood cells tend to have a lower risk of cardiac events, especially sudden cardiac death. That is why it was proposed as a risk marker. In the literature, a desirable value is generally taken to be around 8% or higher, and a value below 4% is considered higher risk.

That said, it's only fair to be clear about the evidence: the fact that a low index is associated with higher risk does not mean that taking Omega-3 supplements is guaranteed to prevent a heart attack. Several large clinical trials of EPA and DHA supplementation produced neutral results in terms of reducing mortality, and recent reviews found no clear benefit on total or cardiovascular mortality. Today it is better understood as a marker associated with risk than as a treatment target with a proven effect.

The Omega-6/Omega-3 ratio is also discussed in relation to inflammation. The idea that a very high ratio (typical of Western diets) promotes inflammatory processes is a reasonable and widely held hypothesis, but the evidence is still debated and inconclusive. In fact, large population studies have found mixed results: in some, this ratio showed no significant association with inflammation markers. It's best to treat this result as general guidance, not as a verdict.

It may be of interest to people who, together with their doctor or nutritionist, want to know their fatty acid nutritional status: for example, people who eat little fish, people who are reviewing their diet with a cardiovascular focus, or people who take Omega-3 supplements and want to see how they are reflected in their body.

Official recommendations point in a simple, well-supported direction: eat fish regularly. The Guías Alimentarias para la Población Argentina (Argentina's national dietary guidelines) suggest including fish at least twice a week, and the FAO/WHO expert consultation recommends a minimum intake of about 250 mg per day of EPA + DHA for adults. The test does not replace these dietary guidelines or a professional consultation: it is a complementary tool.

Important: this test does not diagnose or rule out heart disease on its own, nor does it replace routine checks (blood pressure, cholesterol, blood glucose). Its value lies in providing an additional data point that your healthcare professional interprets within a broader picture.