On May 15th I shared an instagram post about What it Means to be a Female Athlete in support of National Women’s Health Week. It included a list as silly as de-tangling my hair to as serious as motivating myself to run despite menstrual cramps. Later that week I shared my current nutrition struggle of battling anemia and posted high iron foods for female runners. Both of these posts got me thinking about the nutrition concerns of female runners. Rise Up Nutrition is not exclusive to female runners, however this blog post will highlight the extra challenges female runners face from a nutrition perspective.
All runners should consider nutrition when optimizing health and performance, but there are a few concerns that apply specifically to female runners that should not be overlooked.
1. DIMINISHED MUSCLE RECOVERY:
The first nutrition concern of female runners is optimizing muscle recovery. Muscle recovery is enhanced with protein intake and anabolic (growth) hormones including testosterone and insulin. Muscle recovery is diminished by catabolic (break down) hormones like progesterone, adrenaline, and glucagon.
High progesterone levels in women stimulate the accumulation of body fat and catabolism of protein metabolism. This means that during the recovery period after a run, female runners are more likely to break down muscle, more so then they already did during the run, and more so than their male counterpart. This excess catabolism will result in soreness, weakness, and diminished strength over time.
During this recovery period, women are also more likely to store fat. The combination of storing more fat while breaking down excess muscle can lead to a higher body fat to muscle ratio, and an undesirable weight to power ratio.
In addition to progesterone hindering muscle recovery, women also have the disadvantage of low testosterone. Women have testosterone levels ranging 8-60ng/dL, compared to an adult males 240-950 ng/dL, making it significantly harder to build powerful muscles despite the same training or work effort. Though “building muscle” may not be the goal of a female runner, repairing the muscle after a run is the same physiological mechanism of “building muscle.”
Furthermore, when testosterone is low and estrogen is high, the capacity for muscle glycogen (stored energy) to mobilize is lower. This slows the process of recovery, resulting in less energy available for use during a two-a-day run, or back to back hard training days.
THE FIX: OPTIMIZE PROTEIN & CARBOHYDRATE INTAKE AFTER A RUN.
As altering hormones is out of the question, the fix to diminished muscle recovery is optimizing protein and carbohydrate intake during the recovery period. Female runners need more protein and carbohydrates in the recovery period.
The first 30-minutes is when a woman's insulin is most sensitive, which will allow carbohydrates to be optimally stored in the form of glycogen. After this time, glycogen storage diminishes and fat storage increases. Take advantage of this 30-minute window and aim for starchy vegetables like potatoes, corn, and parsnips, or grains such as pasta, cereals, and breads soon after a run.
While insulin is high and nutrients are being shuttled into the muscle, a boost of protein during this time will start the muscle recovery process as well. Many have heard that 20g of protein is an ideal amount, however many women eat only 10-15g thinking that they "don't need to build muscle." As I previously mentioned, this isn't about "building muscle" but rather repairing the muscle to optimize training response, reduce soreness, prevent injury, support ligaments and tendons, improve power output, and sustain high energy output day after day. Between 20 to 30g is going to help overcome the effects of progesterone and lack of testosterone. For 30g of protein try a sandwich with 3oz deli turkey and 1 oz cheese, or a cup of oatmeal cooked with 1 cup milk, 2 Tbsp almond butter, and 2 oz pumpkin seeds.
2. IRON & FATIGUE
The second nutrition concern for female runners is maintaining high iron levels and preventing anemia.
Iron is a mineral which holds oxygen within our red blood cells. When women have low iron, oxygen can no longer be held within the red blood cells. Without adequate oxygen, our muscles are not able to create energy to sustain endurance exercise.
Just as running in high altitude is harder because the air has less oxygen, running with low iron is harder because the blood has less oxygen. Your body will feel fatigued and deprived of energy during runs. If not addressed, this fatigue will be felt during normal activities of daily life as well.
Due to monthly blood losses of the menstrual cycle, female runners are at higher risk of low iron compared to male runners. Furthermore, a female’s lower calorie intake, and higher rates of vegan or vegetarian diets may contribute to higher risk of iron deficiency. Specific to runners, ground impact or “foot strike”, muscle contraction, and gastrointestinal bleeding from prolonged endurance may all contribute to increased iron breakdown. New research also shows that high training intensity increases hepcidin, an inflammatory hormone, which alters the body’s iron homeostasis. All these factors combined put female runners at risk of iron deficiency and anemia.
THE FIX: EAT HIGH IRON FOODS & CONSIDER SUPPLEMENTATION.
High iron foods should be eaten regularly: red meat at least twice a week, poultry, fish, and shellfish regularly. Non-meat iron foods include the skin of potatoes, oatmeal, quinoa, dried fruit like gogi berries and raisins, nuts and seeds including almond butter, spinach and kale. Female runners should get their iron checked annually at a physical or regular check up with their physician to know if they need supplementation. If iron is below 35ug/dL consider a daily iron supplementation. This supplement should not be taken with calcium (such as in milk and cheese) or with oxalates and phytates (such as in tea and coffee) as these nutrients can inhibit absorption.