Nutritional requirements vary depending on the demands we put on our bodies. When recovering from an injury or illness, we often think of including many different modalities - we try ice, heat, massage, physiotherapy, chiropractic, mindfulness meditations - but we often forget that nutrition plays a key role in how fast our bodies are able to recover from an illness or injury.
Nutritional deficiencies can impact the healing process at a number of different stages. These processes are energy requiring, meaning that there’s an increased need for both calories and nutrients during wound healing. Malnutrition or certain nutrient deficiencies can prolong the inflammatory phase, decrease fibroblast proliferation, decrease angiogenesis and alter collagen synthesis, which can lead to decreased wound tensile strength and increased rates of infection. What all that means is, it’s important to get adequate nutrition when recovering from an injury because the body’s metabolic demands go up while it’s hard at work repairing tissue. If enough ‘supplies’ aren’t readily available to repair the damage, your body will actually steal those supplies from healthy tissue. Many clinical studies have shown that nutrition supplementation can enhance wound healing in surgical patients. Just in case you’re saying to yourself, ‘sure, but that assumes a person is already in an unhealthy state to begin with, what if you’re an athlete in their best health who just sprained an ankle?’ Oh, don’t you worry dear reader, I’ve got that covered too. Studies also show that adequate nutrition to avoid malnutrition in athletes is just as important for proper wound healing. Generally, the nutritional recommendations would be to maximize muscle mass and fitness, so would be no different than those for any other athlete with similar goals.
With that in mind, lets quickly go over the healing stages so you have an idea of why it’s important to eat what and when.
Stage 1 – Inflammation [typically lasts up to 4 days post-injury, but can last longer depending on injury] As soon as tissue damage occurs, various inflammatory chemicals are released from the damaged tissue. These chemicals initiate the inflammation process. This process is a cascade event, which means that once started, it goes to completion. You can alter how big of a response you have, but you don’t really have much influence on stopping or interrupting the cascade. This is partly why things can turn into what’s termed ‘chronic inflammation’, where the process becomes self-feeding and never goes to completion. We’re assuming here that you have a normal process that goes to completion and doesn’t become chronic. During this stage, despite an increase of blood flow to the area, injured tissues are deprived of their normal flow of oxygen and blood. Cell death is initiated. During this phase, you typically have the most pain, swelling, redness, and heat.
Step 2 – Proliferation [typically lasts from 4 days to 21 days post-injury]
Once inflammation is beginning to subside, the damaged tissues are removed and replaced with scar tissue, and new vasculature is developed.
Step 3 – Remodeling [typically lasts from 21 days to 2 years post-injury]
The scar tissue begins a process called remodeling where it is slowly replaced with stronger connective tissue. During remodeling, the scar tissue formed as a result of the first 2 phases is broken down and replaced by type I collagen, a much more robust form of collagen. Interestingly, this tissue is laid down upon lines of tension, which means that activities done during this will influence the effectiveness of the repair. This is why I always recommend seeing a good physiotherapist (you can find recommendations here) is a great idea when dealing with injuries.
I’m also going to make a side note here about bone tissue healing versus soft tissue repair. With bone repair, the initial inflammatory phase is similar to soft tissue injury. Osteoblast formation quickly follows the initial injury. Then a cartilaginous callus is formed to provide stabilization of the fracture site. Initially, the callus is incomplete - it’s soft and pretty weak. Since collagen synthesis is an important factor during this time, getting enough collagen to support the healing process is important. This is why they used to feed you jello all the time in the hospital - gelatine is basically the cooked form of collagen. Finally, the cartilaginous callus is broken down and replaced with bone, that then also undergoes remodeling until it is the same as the original it’s replacing. As with soft tissue repair, all of these processes require ample energy, but with appropriate therapeutic and nutritional intervention, the injured area can be as strong as the original, uninjured tissue or even stronger.
Nutrition to Support the Inflammation Phase
As the first step in the recovery process is the inflammatory stage, let’s begin with a discussion of the nutritional management of inflammation. You can see this post here for a more in-depth discussion of the foods, herbs, and spices that all have research backed anti-inflammatory effects. In short, avoid refined carbohydrates and eat more fruits and vegetables. It’s important to note that many polyphenols in plants are fat-soluble, meaning that they are absorbed better by the body in the presence of fat. So eating a diet that includes healthy fats - olive oil, avocado, flax, fish, nuts - can help to increase the amount of the good stuff from plants. Also helpful - omega 3 fats, like those just listed, has also been shown to have anti-inflammatory effects. It’s also a great idea to decrease the intake of corn oil, sunflower oil, safflower oil, cottonseed oil, soybean oil, and other oils high in omega 6 fats, which are known to be inflammation-promoting. This opinion is not universal, however, and more recent evidence suggests that omega-6 fatty acids also have anti-inflammatory properties. So adequate intakes of both types of fatty acids should be encouraged. However, the typical North American gets about ten to fifteen omega 6 fats to every omega 3 fat consumed. An ideal ratio is about two or three omega 6 fats to every omega 3 fat consumed.
As an interesting side note about omega 3’s, there is new evidence to suggest that fish oil supplementation may also be important to protect against muscle loss during immobilization. Now, before you go getting too excited, it was a study done in rodents so we’ll see if it can be replicated in humans, but if you have to be in a cast for any length of time and are taking your omega 3’s for inflammation, it might be a good idea to continue taking them and maybe it’ll help prevent excessive muscle atrophy.
Nutrition to Support the Proliferation and Remodelling Stages
Tissue repair and remodeling place extra demands on the body. During injury repair, metabolic rate can increase anywhere from 15-50%. If an injury results in the necessity to use crutches, energy expenditures go up in the range of 2–3 times that of regular walking. According to the American Society for Parenteral and Enteral Nutrition and the Wound Healing Society, the recommended guideline for calories for optimal wound healing is approximately 30 to 35 kcal/kg/d. The National Pressure Ulcer Advisory Panel (NPUAP) recommends that individuals who are underweight or are losing weight increase their calorie intake to 35 to 40 kcal/kg/d to optimize wound healing.
So, what does that mean, exactly? Here is an example of the energy demands of a 24-year-old male who’s 5’9” and 180 pounds:
Basal Metabolic Rate:
1,826 kcal/day
Energy needs when sedentary:
2,191 kcal/day
Energy needs post-injury:
2,629 kcal/day
Normally, for a healthy adult, protein requirements are approximately 0.8 g/kg/d. While recovering from illness or injury, however, protein intake should be somewhere in the 1g/kg/d range. Older adults especially have an increased protein requirement of 1 g/kg/d to maintain a positive nitrogen balance. If you have a chronic wound, however, the recommended range of protein associated with healing is between 1.25 and 1.5 g/kg/d. If you’re already severely undernourished, have more than 1 wound, or have a stage III or IV pressure ulcer, you may require 1.5 to 2 g/kg/d protein. However, protein levels as high as 2 g/kg/d may contribute to dehydration in older adults and individuals with renal insufficiency so they should be carefully monitored while undergoing treatment with increased protein.
About 1/3 of one’s dietary fat should come from each type of fat (i.e. 1/3 from saturated fat, 1/3 from monounsaturated fat, and 1/3 from polyunsaturated fat). And, although there’s no requirement for carbohydrate during recovery, it’s important to include enough carbohydrate to support brain function and provide adequate micronutrient intake. That said, I want to make a special note about carbohydrates and healing from a colon related surgery - carbohydrates such as dietary fiber and resistant starches are substrates for fermentation in the colon, producing short-chain fatty acids (eg., acetate, propionate, and butyrate) which are the primary source of fuel for colonocytes - the cells of your colon. In fact, intracolonic infusion of these short-chain fatty acids has been found to enhance postoperative colonic healing, especially butyrate, which has shown the greatest effect on colonic healing. Isn’t that neat? The geek in me finds that super fascinating.
Anyway, moving on…
Micronutrients Beneficial for Healing
Micronutrients are trace elements and minerals that the body requires in small amounts. They act as cofactors or participate in enzymes that are critical to cellular metabolism, especially during wound healing. Studies show that because deficiencies of trace elements and minerals are common in the general population, it is recommended that patients take a supplement with trace elements and minerals to ensure optimal wound healing. However, further research is needed to determine the role and appropriate doses of micronutrients in wound healing. Depending on your specific injury or illness, you might require different concentrations of different micronutrients than the ones listed here, especially if you’re already deficient in some of them. I usually recommend that patients get a micronutrient levels test done to determine their baseline before beginning any supplementation routine to take the guess-work out of which vitamins or minerals to supplement. This can ensure that you get the proper nutrition you need and avoid over-supplementation. There are upper limits to many micronutrients (you can see this post on optimal dosaging here) so knowing what you’re starting with is usually a good idea.
That said, these are the general guidelines for what’s minimally required for the healing process:
Vitamin A - Vitamin A stimulates the immune system during the inflammation stage by increasing the number of macrophages and monocytes in the wound. It has been shown to enhance wound healing by stimulating epithelialization and increasing collagen deposition by fibroblasts. Also, the stress of illness and serious injury is associated with vitamin A deficiency, so it’s often recommended to monitor serum levels of vitamin A, retinyl esters, retinol-binding protein, and β-carotene, especially in patients with burns or trauma, and those who have undergone extensive surgery. Vitamin A supplementation is also indicated to enhance healing in patients with comorbidities (including diabetes, tumors, and radiation) and acute or chronic wounds. Supplementation with 10,000IU daily for the first 2-4 weeks post-injury is usually a safe approach, although, beyond that, the supplement should be removed to avoid toxicity. It’s also important to note that Vitamin A can reverse the anti-inflammatory effects of corticosteroids on wound healing. For patients requiring long-term corticosteroid treatment, topical or systemic administration of vitamin A can correct delayed wound healing. For individuals receiving corticosteroids, oral administration of 10,000 to 15,000 IU/d is recommended to enhance wound healing. More information is available on the DRIs at http://www.nap.edu.
Vitamin C - Vitamin C, also known as ascorbic acid, functions in the synthesis of collagen connective tissue protein. Vitamin C acts on fibroblast proliferation, capillary formation, and enhances neutrophil and lymphocyte activity during phase 1 of acute injury. Vitamin C supplementation has also been shown to enhance healing of wounds and burns. Vitamin C supplementation at 100 to 200 mg/d is recommended for patients who have vitamin C deficiency or wounds, including stage I or II pressure ulcers. For more complex wounds, including stage III or stage IV pressure ulcers or severe trauma, supplementation of 1,000 to 2,000 mg/d orally has been suggested until healing occurs. However, it’s also important to note that high-dose vitamin C supplementation may be problematic in patients with a tendency to form kidney stones.
Copper - Impaired wound healing has been observed in the instance of copper deficiency. Copper is an important cofactor for cytochrome oxidase and the cytosolic antioxidant superoxide dismutase. It has been shown to be necessary for the interaction of lysyl oxidase that is essential for cross-linking and strengthening of the collagen framework. It also assists in the formation of red blood cells and acts in concert with vitamin C to form elastin and to strengthen connective tissue. Supplementing 2-4mg/day during the first 2-4 weeks post injury is recommended.
Magnesium - Magnesium is an important trace element that functions as a cofactor for enzymes necessary for protein and collagen formation and tissue growth. Magnesium interacts with adenosine triphosphate to support to the processes for collagen synthesis during wound healing. However, research on the appropriate dose during wound healing is still controversial.
Zinc - Zinc is an essential mineral required for the catalytic activity of approximately 100 enzymes, and it plays a role in immune function, DNA synthesis, protein and collagen synthesis, cellular proliferation, and wound healing. Zinc plays a critical role in tissue regeneration and a deficiency has been associated with poor wound healing. The daily recommendation for zinc intake is 11 mg/d for men and 8 mg/d for women. The recommendation for zinc supplementation to enhance wound healing is up to 40 mg (176 mg zinc sulfate) for 10 days. It’s important to note that excess zinc interferes with iron and copper absorption and can lead to a deficiency of these important minerals, so there is an upper limit to how much you want to take and for how long.
Arginine - this may stimulate insulin release and growth factors which assist in protein synthesis, collagen deposition, cellular growth, and connective tissue deposition. Its role in stimulating nitric oxide production may increase blood flow to the injured area and activate macrophages for tissue clean-up. Investigators have shown that arginine supplementation can enhance wound tensile strength in acute wounds and supplementation is recommended for wound healing if depletion of body stores is in question because of the stress of illness. Human doses range from 15-30g per day.
Ornithine - Ornithine can improve protein metabolism, shorten healing time, increase healing strength, and increase nitrogen retention. Dosing has been in the 20-30g per day range (10g 2-3x per day).
Glutamine - Glutamine is the most abundant amino acid in the plasma; it provides 60% of the free intracellular amino acid supply and 20% of the total circulating free amino acid pool. Glutamine is a nitrogen donor for the synthesis of other amino acids, is critical for the synthesis of nucleotides in cells, including fibroblasts, epithelial cells, and macrophages, and is essential for gluconeogenesis, providing fuel during wound healing. It is essential for the metabolism of cells that have rapid turnover, such as lymphocytes and enterocytes. Glutamine is also involved with immune function via lymphocyte proliferation and is important in stimulating the inflammatory response during the inflammatory phase of wound healing. During times of stress, glutamine needs increase. Supplementation with glutamine has been shown to improve nitrogen balance and enhance immune function after major surgery, trauma, and sepsis. However, studies have not examined the effect of glutamine on wound healing. The suggested dose of supplemental glutamine for wound healing in adults is 0.57 g/kg/d. However, there are no evidence-based guidelines specifically addressing the safe use and dosage of glutamine to heal chronic wounds, so more research needs to be done.
And of course, ensure proper hydration during injury recovery, as hydration is very important. See this post here to learn why! Also, you can check out the recommended Dietary Reference Intakes (DRIs) for macronutrients and micronutrients are available at here. You can also find a handy, easy to follow, simpler summary guide here.