Episode 145 – Common Dietary Deficiencies in Athletes and How to Avoid/Address Them

Key Topics Covered

Athlete eating food.

In this episode, we cover a range of nutrients. There are a two to be aware of in terms of deficiencies, however there are others that are also commonly under consumed.

Iron Deficiency

Iron Rich Foods

  • Iron deficiency is common in general, particularly in menstruating women. 
  • But with athletes it is even more important for a few reasons.
  • 1) Iron losses can be higher in some cases due to things like sweating, GI bleeding (if relevant) and the breakdown of red blood cells due to impact from things like running.
  • 2) It impacts performance.
    • Iron  transports oxygen from the lungs to the rest of the body. It plays a role in immune function and it also plays a role in fatigue. 

How to Avoid Deficiencies

  • Prioritise iron rich foods. 
  • For omnivores, red meat is often talked about as a good source of iron, but it’s overlooked that other options like fish and chicken still contain iron. 
  • In terms of plant-based sources, some great options are fortified cereal & grain products, tofu, TVP, legumes, fortified mock meats, edamame, amaranth, and some nuts & seeds (sesame and pumpkin seeds).

Recommended Daily Intake & How to Track Intake

  • Using a tool like Cronometer can be useful to see how much dietary changes actually matter. 
  • For example, 200g of red meat has 5mg of iron, but the RDI for menstruating women is 18mg.
  • If you are plant based, this increases by 80%, so this 18mg is then 32mg.
  • ~150g of hard tofu contains roughly 4-5mg of iron.
  • Sometimes people add some red meat 1-2x per week and it doesn’t really move the needle much on their iron status. But when you look at it through this lens, it makes sense 

Vitamin D Deficiency

Person getting sunlight.

  • At a population level, a 2023 pooled analysis of research involving 7.9 million participants found that globally, 16% were really deficient with less than 30nmol/L.
  • Making it a bit broader – 48% of the participants were pretty low at <50nmol/L.
  • And if we pool everyone who had suboptimal levels <75nmol/L that was 77% of the group.
  • With athletes specifically, it really depends on the sport. Sports where a lot of training sessions or games take place outdoors, vitamin D deficiency is rare, since there is plenty of sunlight.
  • Alternatively, sports where there is a lot of time spent indoors see a high prevalence of deficiency.

How to Address This

  • Two main ways to address this: Get more sunlight or use supplements
  • Food is an option but there are not many dietary sources of vitamin D. Supplementation easier for most people. 
  • 1000IU is a standard dosage for capsules, but there are many cases where you may need to go higher. 

Everything else we will talk about won’t necessarily be about deficiency, but more about just trying to optimise intake.

Omega-3

Sources of omega 3

  • Just like omega-3’s for the general population – some people have a great dietary intake and some don’t. 
  • Among omnivores, typically the easiest way to determine if this is if you consume 2-3x servings of fish per week. 
  • Some plant based sources include chia seeds, flaxseeds, hemp and walnuts.
  • These are in the ALA form, which need to be converted to EPA & DHA, which is quite an inefficient process. Therefore, you are likely going to benefit from having a plant-based omega-3 supplement such as algae oil.

Benefits

  • Omega 3 has a bunch of potential benefits ranging from anti-inflammatory benefits, heart health, joint health, cognitive function and potentially other areas such as limiting muscle loss during immobilization post injury/surgery. 
  • A lot of these benefits seem small or inconsistent in research. But they likely also scale based on baseline omega 3 intake and levels

Calcium

Calcium rich foods.

  • The RDI for calcium is actually quite high and athletes are probably more likely to reach this than non-athletes due to a potentially higher food intake overall.
  • However, it’s also not uncommon for athletes to do certain dietary approaches to result in a low calcium intake e.g. cutting out dairy without replacing the calcium.
  • Unfortunately we can’t test calcium levels on a blood test to see if intake is appropriate. This is because your body tightly regulates blood calcium levels, so it pulls calcium content from bones when needed.
  • Therefore, we need to focus more on intake.
  • Beyond the minimum needs, the main reason why calcium is important is for bone mineral density. This can be relevant for things like stress fracture risk.

RDI

For pre-menopausal women and men under 70, this is 1000mg per day.

Dietary Sources

  • 250ml cows milk = 300mg.
  • 40g cheddar cheese = 240mg.
  • John west calcium range = 800mg.
  • 100g spinach = 100mg (thats a lot of spinach).
  • 250mls Vitasoy Calcium fortified milk = 240mg.

Magnesium

Magnesium rich foods.

  • Magnesium is another common nutrient that people often under consume. 
  • Sub-clinical deficiency is reportedly quite common based on some research, however it is hard to test.
  • Athletes with good diets will typically have good intakes of magnesium. Athletes with poor diets will often have poor intakes. It is found in a lot of “healthy” foods.
  • Magnesium is involved in a large variety of functions – muscle contraction, energy production, bone health and in certain cases, prevention of cramps.
  • The research also indicates that people with higher magnesium intake typically get better sleep too.
  • To address this, increasing intake of things like green vegetables, nuts, seeds and whole grains can be an easy win

Vitamin B12

Vitamin B12 foods.

  • This is more common for plant based/vegan athletes and non-athletes.
  • In practice, it is fairly frequent to see sub-optimal intakes of B12 leading to fatigue and poor performance.
  • If left unresolved, it can lead to peripheral neuropathy too.
  • B12 is really hard to get enough of on PB diet, so I always recommend supplementing appropriately.

Supplement Dosage

  • 200-500mcg cyancobalamin daily or 1000mcg 2-3x per week.

Summary

  • Iron and Vitamin D are the two main deficiencies, but there are a lot of common situations where intake is sub-optimal and can be worth addressing. 
  • To optimize performance, it makes sense to have awareness of all of these.

Relevant Blogs / Resources

Blog Posts:

Relevant Studies: