Categories: Food 301

More Energy & Less Fatigue on the Trail: Spotlight Iron

Do your trail foods include iron? Iron plays a vital role in your hiking performance. Foremost, it is necessary to deliver oxygen to your muscles. Getting enough iron in your trail diet will also keep your immune system strong and prevent fatigue. Here we discuss strategies you can use to boost your iron levels.

Photo: Star fusion by Nicolle Rager Fuller/NSF (Source)

Iron is, by mass, the most common element on Earth. It is formed via fusion in stars, comprising almost all of the earth’s core and the planets in the Solar System. It is an essential mineral for both animals and plants. In plants, it plays a role in the production of chlorophyll. In animals, it transports oxygen to the tissues in the body.

Because iron is a requirement for the survival of living organisms, a wide range of foods provide iron. Despite iron’s bountifulness, iron deficiency is widespread in humans. In fact, iron is the most common nutrient deficiency in the world and the most prevalent cause of anemia worldwide.[1]

Why Iron is Important for Hikers

Iron is the most considerable mineral present in human blood. Perhaps the most important function of iron in the body is the production of hemoglobin and myoglobin, which are necessary to transport oxygen in the blood. About 65% of iron exists in hemoglobin, a protein in red blood cells. A smaller amount of iron is in myoglobin, a form of hemoglobin found in muscle. Myoglobin supplies oxygen to the muscles and provides energy during physical activity.

If your iron is low, you will generate fewer red blood cells, and hemoglobin levels will decline. Consequently, less oxygen will be transported to your muscles, and your hiking performance will suffer. Your pace will slow because your muscles won’t have the energy to work.

Healthy red blood cells versus unhealthy red blood cells. Iron is the main component of red blood cells where it binds with hemoglobin and oxygenates red blood cells. RBCs are pale and poorly formed if they’re deficient in iron.

Although a loss of this metal occurs with physical activity and blood loss, the body has no innate mechanism to replace these losses. Therefore, you must consume iron-rich foods to keep your levels up.

There are two types of dietary iron:

Heme iron: This iron is only found in animal foods and is very well absorbed. When eating meat, you consume the hemoglobin and myoglobin blood proteins in the animal’s flesh. The amino acids in animal cells are comparable to human cells’ patterns. This means that it is easily digested and used by the body. Red meat, organ meat, and shellfish contain unusually high amounts of heme iron. This does not mean you need to eat animals to get iron.
Non-heme iron: This type is more common and is found in animal and plant foods. It is not as easily absorbed as heme iron. According to the American Red Cross, humans absorb up to 30 percent of heme iron, compared with 2 to 10 percent of non-heme iron. If you consume plant foods with vitamin C, iron absorption improves. Beans, lentils, peas, and dark chocolate are rich in iron.

Vegetarian Backpacking Food Sources of Iron

It’s estimated that in general, we need at least 8 mg of iron daily (males) and 18 mg (reproductive, non-pregnant females)^[2]. Endurance activity and heavy exercise increases this need slightly, which means thru-hikers are likely not getting enough iron on the trail.

Increasing your dietary intake of iron will replenish losses from heavy exercise. It is not possible to overdose on iron from food. A wide range of food contains iron. I’ve outlined some of the best plant sources of iron here:

Legumes: lentils, kidney beans, chickpeas, soybeans, tofu, tempeh, lima beans
Dark chocolate (70% or more)
Grains: quinoa, oatmeal, fortified cereals (often bran), seitan/wheat gluten, brown rice
Nuts and seeds: pumpkin, pine, pistachio, sesame, sunflower, cashews, almonds
Dried fruit: apricots, raisins, prunes
Blackstrap molasses (Molasses cookies)
Vegetables: tomato, dark leafy greens.

Increase your Iron Intake if you:

Eat poorly

Iron deficiency is primarily caused by insufficient intake. Picky eaters and those who eat an unbalanced, monotonous diet are likely deficient. Contrary to popular belief, vegetarians and vegans do not have a higher incidence of iron deficiency than meat eaters — unless they eat poorly.[3] The caveat is that vegetarians must be more diligent than omnivores. Because heme iron (from meat) is more bioavailable to the body than non-heme (from plants), omnivores can eat poorly and maintain a good iron status. Vegetarians will need to consume an abundance of iron-rich plant foods with vitamin C foods.

Have a digestive disorder

People suffering from gastrointestinal disorders, such as celiac disease and irritable bowel disease, are not able to properly absorb iron from foods. Iron can be blocked due to hepcidin bursts (hepcidin is a hormone that regulates iron absorption). Excessive consumption of tea and coffee can also cause iron malabsorption. Consume tea 1 hour after a meal to improve iron absorption.^[4]

Lose blood

Women with heavy periods or frequent blood donors can become deficient in iron if the losses are not replaced in the diet. Disorders that cause digestive tract bleeding (such as ulcers, chronic NSAIDs or aspirin use) can also contribute to low iron.

Participate in endurance exercises, such as thru-hiking

Interestingly, long-distance endurance activities, such as fast packing, trail running, and long mileage walking (thru-hiking), can cause iron deficiency due to the mechanical trauma of the foot repeatedly striking the ground. Research in this area is lacking, but it appears that consecutive exercise, especially on hard surfaces and downhills causes hemolysis or destruction of the red blood cells during footstrike; consequently, this releases both hemoglobin (Hb) and iron into the surrounding plasma which becomes lost and contributes to iron deficiency[5].

Although iron losses from sweat are minimal, repeated exertion accompanied by heavy sweating is another contributor.

In unsanitary conditions

Another overlooked cause of anemia that can strike hikers and wilderness travelers is from walking barefoot on contaminated soil, drinking untreated water, or consuming contaminated dirt that may be present on the hands or under the fingernails. This type of anemia is caused by infestation with parasitic worms, commonly hookworms. The parasitic worms cause inflammation and chronic blood loss by binding to the small intestine and competing for nutrients. Symptoms may not be present.^[6]

In summary, the causes of iron deficiency include:

Inadequate iron intake (not eating enough iron-rich foods)
Loss of iron through blood (frequent blood donors, menstruating females)
Bleeding in the digestive tract (such as from ulcers, chronic NSAIDs or aspirin use)
Destruction of red blood cells through footstrike or hemolysis (most common in long-distance runners)
Loss of iron due to parasite infestation (commonly hookworm infestation when left untreated)
Loss of iron through heavy sweating (losses from sweat are minimal but can add up with repeated exertion)
Iron malabsorption (due to inflammation in the gut, celiac disease, etc.) and blockage of iron absorption due to hepcidin bursts (hepcidin is a hormone that regulates iron absorption)

Key Indicators that you have an Iron Deficiency

If you are severely iron deficient, you may experience all these symptoms, while someone in the first stages might experience few to no signs.

Pale skin
Swollen tongue
Inability to maintain body temperature; Cold hands and feet.
Impaired immunity.
Shortness of breath.
Feeling tired and weak. You can feel weak and tired when your iron levels are too low — or too high. Yes, having too much iron can also cause fatigue. Because iron is stored in the body, having an excess can make you feel tired and contribute to other problems. Getting too much iron is rarely a problem unless you take an iron supplement, which you should not do unless you have been diagnosed as anemic.
PICA (craving for ice, dirt, and other nonfood items)

Your Fix:

Strategies to boost your iron levels.

Increase your intake of iron from natural food sources. Vegetarians will need to consume more nonheme iron than meat eaters.
Eat nonheme iron foods with Vitamin C foods. Absorption of nonheme iron is enhanced by Vitamin C, also called ascorbic acid.^[7]When they’re digested together, vitamin C combines with nonheme iron to form a compound that’s more easily absorbed. The level of absorption varies depending on the amount of Vitamin C ingested
The level of absorption varies depending on the amount of Vitamin C ingested. Still, research shows you only need a small amount, typically one serving of a fruit or vegetable, or about 25 milligrams of vitamin C. Unfortunately, Vit C is greatly depleted during cooking and dehydration. For vegetarian hikers, we recommend adding Vit C to meals/water. For water, add camu camu, Emergen-C, or lemon powder; for meals, add freeze dried berries and red bell pepper.
Cooking nonheme iron foods increases iron availability. You are also likely to eat more leafy greens by mass, for example, spinach and collards, when it cooks down. Iron is not destroyed by cooking or drying.
At home, keep iron levels high by cooking with a cast iron skillet. Traces of iron from the skillet do get absorbed into the food.^[8]
Supplement if you are low. Striking the right balance is essential, so don’t self-diagnose and take iron pills. Go to your doctor first and ask to have your ferritin (stored iron) and hemoglobin levels checked. If you already know you are chronically low, have your levels checked and monitored by a doctor. You should never supplement with iron unless you truly need it because too much can be toxic. Because no physiologic mechanism exists to excrete excess iron from the body other than blood loss (i.e., pregnancy, menstruation, donating blood), it is very possible to get too much iron if you supplement.

Iron Fix Trail Mix

Munch on this mix between meals to keep your iron stores up. Mix a variety of any of the following:

Pistachios
Sunflower Seeds
Pumpkin Seeds
Cashews
Almonds
Apricots
Raisins
Date Pieces
Dark Chocolate Chips
Quinoa Crisps

Other good snack options for the trail include hummus mix and dark cocoa with soymilk.

Image: clipartxtras.com

Spinach’s reputation as a muscle builder, popularized by Popeye, resulted from a misplaced decimal point when calculating its iron content. It was believed to be 10x more iron-rich than it actually was. There is only 3.5 milligrams of iron in a 100-gram serving of spinach, but the accepted fact became 35 milligrams. While cooked spinach is an okay source of iron, it also contains oxalates which block the absorption. There are much better iron-rich food choices.

Are you getting most of your trail calories from junk foods? This often results in vitamin deficiencies, significantly contributing to fatigue and illness among hikers. Here’s to staying active and healthy by eating delicious and nutrient-rich foods.

Unless the body is deficient in a nutrient, supplementing with vitamins and minerals will not improve hiking performance. Taking vitamins is a good idea if you eat a poor or restricted diet. This guide is meant to identify and prevent iron deficiency.

References

[1] Miller, J. (2013). Iron Deficiency Anemia: A Common and Curable Disease. Cold Spring Harbor Perspectives In Medicine, 3(7), a011866-a011866.doi:10.1101/cshperspect.a011866
[2] Office of Dietary Supplements – Iron. (2018). Ods.od.nih.gov. Retrieved 28 November 2018, from https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/
[3] WJ, C. (2018). Iron status of vegetarians. – PubMed – NCBI . Ncbi.nlm.nih.gov. Retrieved 28 November 2018, from https://www.ncbi.nlm.nih.gov/pubmed/8172127
[4] Ahmad Fuzi SF, e. (2018). A 1-h time interval between a meal containing iron and consumption of tea attenuates the inhibitory effects on iron absorption: a controlled trial … – PubMed – NCBI . Ncbi.nlm.nih.gov. Retrieved 28 November 2018, from https://www.ncbi.nlm.nih.gov/pubmed/29
[5] Cosimo Ottomano, M. (2012). Sports anemia: facts or fiction?. Blood Transfusion, 10(3), 252. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417720/#b15-blt-10-252
[6] CDC – Hookworm. (2018). Cdc.gov. Retrieved 28 November 2018, from https://www.cdc.gov/parasites/hookworm/
[7] JD, L. (2018). Interaction of vitamin C and iron. – PubMed – NCBI . Ncbi.nlm.nih.gov. Retrieved 28 November 2018, from https://www.ncbi.nlm.nih.gov/pubmed/6940487
[8] Geerligs PD, e. (2018). Food prepared in iron cooking pots as an intervention for reducing iron deficiency anaemia in developing countries: a systematic review. – PubMed – NCBI . Ncbi.nlm.nih.gov. Retrieved 28 November 2018, from https://www.ncbi.nlm.nih.gov/pubmed/1