Have you ever found yourself chewing cups of ice throughout the day? Many bariatric patients report this behaviour after their bariatric surgery. While chewing ice does not necessarily mean you have low iron levels, it does warrant getting your iron levels checked.
Iron deficiency is one of the most common deficiencies after bariatric surgery. This article explains the role of iron, the symptoms of iron deficiency, why bariatric patients need more iron, which blood tests are used, food sources, types of iron supplements and how to improve absorption.
Key takeaways
- 25–50% of bariatric surgery patients develop an iron deficiency, often within 6–9 months after surgery, and the risk increases over time.
- Less stomach acid and, after a gastric bypass or duodenal switch, bypassing the primary area of iron absorption reduce iron uptake.
- Iron needs vary widely after surgery – regular blood work is the only way to set your individual recommendation.
- Separate calcium and iron by at least two hours and avoid black tea or coffee 1 hour before and after taking iron.
- Never start or increase iron without talking to your bariatric surgeon and/or dietitian.
Iron's role
Iron is a key element in the metabolism of all living organisms and helps to make up hundreds of proteins and enzymes. Iron has many functions; below are some of the key ones.
- Haem: the iron-containing compound found in molecules.
- Haemoglobin and myoglobin: haem-containing proteins that help to transport and store oxygen.
- Haemoglobin is the primary protein in red blood cells and makes up two thirds of the body's iron. It helps to transport oxygen from the lungs to the rest of the body.
- Myoglobin transports and stores oxygen (short-term) for muscle cells. This is extremely important when the muscles are working, such as during physical activity.
- Energy: iron is involved in electron transport (synthesising ATP, the primary energy storage compound in cells) and energy metabolism.
- Antioxidant: iron acts as an antioxidant.
- DNA: iron assists with DNA synthesis.
Symptoms of iron deficiency
There are many symptoms related to iron deficiency, including:
- Fatigue (low energy levels)
- Increased heart rate and heart palpitations, especially during physical activity
- Rapid breathing on exertion
- Decreased athletic and physical work capacity
- The inability to maintain a normal body temperature
- Brittle and spoon-shaped nails
- Sores at the corners of the mouth, diminished (less sensitive) taste buds and a sore tongue
- Some forms of hair loss
- Pica: eating non-food substances, such as clay or cornflour, or chewing ice
- A lower immune status (more likely to catch a cold or get sick)
- Dry, scaling, cracking or itchy skin
- Confusion, headaches, decreased mental capacity, amnesia and irritability
- Restless leg syndrome, dizziness and depression
If iron deficiency continues and is advanced, it can lead to difficulty swallowing due to the formation of webs of tissue in the throat and oesophagus.
These symptoms can have many causes. If you recognise them, ask your bariatric team or GP to check your iron levels.
How much iron?
The recommended dietary allowance (RDA) was developed for the general, healthy population, and these recommendations do not always apply to bariatric surgery patients.
| Group | Iron per day |
|---|---|
| Males (all ages) and post-menopausal females | 8 mg |
| Menstruating females | 18 mg |
| Bariatric surgery patients | Varies: some require only 18 mg, others as much as 100 mg or more |
It is very important to get an iron panel checked via blood work so your bariatric surgeon or GP can determine your individual iron recommendation.
Why do bariatric patients require more iron?
There are several reasons why bariatric surgery patients require more iron after surgery than before:
- Low levels before surgery: as many as 35–44% of pre-op bariatric patients have low iron levels prior to their bariatric surgery.
- Less stomach acid: there is less stomach acid after bariatric surgery, and iron needs acid to aid its absorption.
- Deficiency after surgery: post-operatively, about 20–50% of patients experience an iron deficiency and the risk increases over time. One study reported that half of the patients were getting the recommended amount of iron and were still deficient, which further explains the need for individualised recommendations and continued blood work.
- A multivitamin may not be enough: a daily multivitamin may not prevent an iron deficiency, since so many patients require more than what is included in their daily multivitamin.
- Stores run out: the risk of iron deficiency increases over time as the body eventually runs out of iron stores.
- Bypassed absorption site: with a gastric bypass, the primary area of absorption for iron is bypassed, which further increases your need for iron supplementation. This same area is also bypassed in the duodenal switch.
- Food intake: post-operatively, there may be incomplete digestion of protein, and many patients have an aversion to iron-rich foods such as red meat. Red meat tends to be one of the top five foods that bariatric patients do not tolerate very well (although every patient is different in what they do and do not tolerate after surgery).
- Decreased absorption: there is decreased absorption of iron after gastric bypass and biliopancreatic diversion with or without duodenal switch.
As many as 25–50% of bariatric surgery patients develop an iron deficiency. This often happens within 6–9 months after bariatric surgery, although it may take 3–4 years to develop.
Maintenance level/daily dose vs. waiting
You should always follow the instructions of your bariatric surgeon, who knows your individual medical history and blood work. Still, it helps to understand why some bariatric surgeons have patients start iron immediately after surgery while others do not. There are two schools of thought:
- Monitor first: some bariatric surgeons prefer to monitor lab levels and have patients start iron once their iron levels start to drop.
- Daily dose: others prefer patients to start a daily dose of iron shortly after surgery to prevent levels from dropping.
Either way, the most important thing is to keep getting your blood work done as recommended, so your iron supplementation can be adjusted as needed and you can maintain normal iron levels, leaving you feeling energised and healthy.
Iron laboratory studies
It is important to get your iron levels checked in the morning while fasted, as levels can change throughout the day. While ferritin is the normal lab parameter for iron in the general population, it may not be the best parameter for bariatric patients. Ferritin is typically a sign that iron stores are dropping and is normally seen as the primary sign of iron deficiency. However, ferritin is also an indicator of inflammation, and obesity is a disease of inflammation.
There are three levels of iron-deficient states:
| State | Lab values | What it means |
|---|---|---|
| Anaemia | Low serum iron, low MCV (mean corpuscular volume), high TIBC (total iron binding capacity) and high transferrin | – |
| Depletion | Serum iron between 60–115 mcg/dL and TIBC between 360–390 mcg/dL | Iron stores are depleted, but there is no change in the functional iron supply yet |
| Iron deficiency anaemia | Low MCV, low MCH (mean corpuscular haemoglobin), low haematocrit, low haemoglobin, serum iron below 40 mcg/dL, ferritin below 10 ng/mL, TIBC above 390 mcg/dL and transferrin below 15% | There is inadequate iron to support normal red blood cell formation (the cells formed are smaller and have less haemoglobin), which means inadequate oxygen delivery and/or suboptimal function of iron-dependent enzymes |
Early functional iron deficiency means that the supply of functional iron is low enough to impair red blood cell formation, but there is no anaemia yet.
Food sources of iron
There are two types of iron from food: haem and non-haem iron. Haem iron is found in haemoglobin from animal foods, such as red meat, fish and poultry. The body absorbs more iron from haem sources than from non-haem sources. Iron in plant-based foods, such as lentils, beans and dark leafy greens, is non-haem iron. This is also the form added to iron-enriched and iron-fortified foods and supplements. Our body is less efficient at absorbing non-haem iron, but most food sources of iron are non-haem.
Haem iron sources (per 85 g serving)
| Iron per serving | Foods |
|---|---|
| Very good: 3.5 mg or more | Clams, molluscs, mussels or oysters |
| Good: 2.1 mg or more | Cooked beef, tinned sardines (in oil) and cooked turkey |
| Other: 0.7 mg or more | Chicken, halibut, haddock, perch, salmon, tuna, ham or veal |
Non-haem iron sources
| Iron per serving | Foods |
|---|---|
| Very good: 3.5 mg or more | Breakfast cereals enriched with iron, cooked beans (approx. 170 g), tofu (approx. 125 g) and pumpkin, sesame or squash seeds (28 g) |
| Good: 2.1 mg or more | Tinned lima beans, red kidney beans, chickpeas or split peas (approx. 90 g), dried apricots (approx. 130 g), 1 medium baked potato, 1 medium stalk of broccoli, cooked enriched egg noodles (approx. 160 g) and wheat germ (approx. 30 g) |
| Other: 0.7 mg or more | Peanuts, pecans, walnuts, pistachios, roasted almonds, roasted cashews or sunflower seeds (28 g), dried seedless raisins, peaches or prunes (approx. 80 g), spinach (30 g), 1 medium green pepper, pasta (approx. 140 g cooked), 1 slice of bread, a pumpernickel bagel or bran muffin, or rice (approx. 160 g cooked) |
Types of iron
There are several types of iron salts when it comes to supplementation. One of the common iron salts recommended to the general public, ferrous sulphate, has only 20% elemental iron available.
What does elemental iron mean? The dosage listed on a label typically needs to be multiplied by the percentage of elemental iron of that iron salt to determine how much iron is actually absorbed (how much the body can actually use). Please keep in mind all Celebrate® products list our dosages as the elemental dosage and you do not have to do this math (YAY!).
| Iron salt | Elemental iron |
|---|---|
| Ferrous gluconate | 12% |
| Ferrous sulphate | 20% |
| Ferrous fumarate | 33% |
Ferrous fumarate is the most recommended iron salt due to its higher bioavailability with 33% available as elemental iron. Ferrous fumarate is also gentler on the stomach (i.e., less constipating), another reason why it is the most common type of iron used in the bariatric surgery patient population.
How to increase the absorption of iron
There are ways to make sure you get the most out of your iron supplement. Make sure your iron supplement also contains vitamin C to enhance iron absorption, or add vitamin C to the iron you are taking (talk to your bariatric surgeon and/or dietitian before making any changes to your supplement regimen).
- Do not take calcium at the same time as your iron or a multivitamin containing iron. Separate calcium and iron by at least two hours.
- Do not take your iron product with calcium-rich foods, such as a glass of milk.
- Do not consume a high amount of tannin-rich products (tea, wine, chocolate, coffee) throughout the day. This is especially important if you are trying to increase your iron levels.
- Avoid black tea or black coffee 1 hour before and 1 hour after taking your iron (especially important if you are trying to increase your iron levels).
- Consider checking your vitamin A status if you are having trouble correcting your iron levels. Sometimes, once vitamin A levels are within normal limits, iron is better absorbed.
- Adequate copper status is also important for normal iron metabolism.
Drug–nutrient interactions
There are also a couple of drug–nutrient interactions with iron. These may not be avoidable if you are told to take these medications, but they further increase the need to get your iron levels checked as recommended by your bariatric surgeon.
- Proton pump inhibitors (PPIs) and H2 receptor antagonists decrease the absorption of iron. These medications are commonly used to treat heartburn or oesophageal reflux (GERD).
- Thyroid medication (such as Synthroid or levothyroxine): talk to your bariatric surgeon and/or pharmacist about the timing of your bariatric vitamins, as you may need to change the dosing schedule.
Tolerating your iron
If your individual iron recommendation is on the upper end, talk to your bariatric programme about starting at a lower dose and increasing to the recommended level to decrease the risk of tolerance issues. If you have any stomach upset when taking your iron, talk to your surgeon and/or dietitian about taking it with food. Make sure you do not take it with calcium-rich foods.
Too much of a good thing?
Iron can be toxic, so do not take more or start iron without talking to your bariatric surgeon and/or dietitian and getting blood work done. The upper limit is set at 45 mg/day, but keep in mind this is for the general population. There is plenty of research showing that many bariatric patients require more than 45 mg/day to maintain their levels within normal limits. Please keep your iron supplement out of the reach of children, as it can be very dangerous to them if taken accidentally.
Iron deficiency is one of the most common deficiencies seen in post-operative bariatric patients, but it is also one of the most preventable, since we have good lab parameters to evaluate an individual's iron stores. Follow the instructions of your bariatric programme regarding iron supplementation and get follow-up blood work done in a timely manner. This will help you keep your iron levels within normal limits, feel healthy and energised, and keep CELEBRATING your successes!
This article is for general information only and does not replace personal medical advice. Always discuss your situation, blood test results and supplementation with your bariatric team or healthcare provider.