Adapting your nutritional intake to speed recovery from injury is a practice that is most likely largely overlooked by many athletes, particularly non-professionals. However, in order to speed up the recovery process certain nutritional practices can be adopted to aid this process. The following article will explore these strategies that will get you back training and competing as quickly as possible. (Note: these strategies need to be undertaken with an appropriate rehabilitation programme for maximum effectiveness)
Soft tissue repair process
Soft tissue injuries are the most common in sport and exercise, and most typically affect muscle, tendon, ligament and bone. Although the injury and the associated pain, swelling and dysfunction may be perceived as a chaotic process, biologically and physiologically there is an organised, consistent pattern followed during the repair process.
Excepting bone, this predictably follows a three stage process of inflammation, proliferative and remodelling phases. The first inflammatory stage is characterised by pain, swelling, redness and heat and in the case of acute injury will typically last up to 4 days post-injury. Independent of the type of tissue injured, the damaged area will be deprived of oxygen and nutrient-rich blood and this will result in cell death. This sets in motion a process to remove the dead and damaged cells and lay down new ones. During the inflammatory stage there is a migration of inflammatory and immune cells into the site, which attract plasma and proteins, and consume all the dead cells. It should be noted that the purpose of any injury management programme should not be to stop the inflammatory stage as it is absolutely essential to the recovery process. The prescription of NSAIDS (anti-inflammatories) was once common practice, but this is now believed to be contra-indicatory and not current best practice during this stage.
The proliferative stage will typically occur from day 4 to day 21, and will proceed once inflammation has started to subside. Damaged tissue will now have been removed and new blood vessels will be getting laid down. This will allow the return of oxygen and nutrients, and also fibroblasts, which will allow the formation of scar tissue. This scar tissue will be laid down in alignment with the forces that are placed on the site (highlighting the importance of rehab exercises in this stage). This scar tissue will eventually reduce in size during this phase.
The remodelling stage will typically occur from 21 days to as long as 2 years depending on injury severity. The scar tissue formed in the previous stage is made from type II collagen fibres and this will now be replaced by stronger type I collagen fibres. It is unlikely that 100% of previous functionality will be re-attained, but at least 80% can be. It should be noted that to optimise return to near normal function, an appropriate rehabilitation programme should be followed. Manual therapy and certain drug interventions can aid recovery, but physical therapywill form the major part of rehabilitation.
Bone repair, while following a similar process, has its own unique distinctions. Stage 1 is also an inflammatory phase, but this will last up to 2-3 weeks. Stage 2 is the formation of a soft callus and will take place in the period of 2-3 to 4-8 weeks. The pain and swelling will have decreased and new bone will start to form through the action of osteoblasts and chondroblasts. Stage 3 (4-8 to 8-12 weeks) will see the hardening of the callus with a bridge of new bone forming between the fracture, as the cartilage and woven bone forms lamellar and then trabecular bone. Finally a fourth stage (8-12 weeks to up to several years) sees remodelling of the bone occur with any deformities in the fractured area being corrected.
Nutritional approaches to injury management and the promotion of healing
As has been noted above a number of different therapies can be utilised to aid recovery from soft tissue injury. One approach that is often overlooked however is the use of nutrition. Now that we have a better understanding of the injury recovery process, we can now look at the three different areas that can positively impact both the nature and speed of recovery.
Firstly, we would want to look at ways that not only support, but manage, the acute inflammation stage. Secondly, it is a desirable goal to support immune function. Thirdly and finally, it is important to support long term tissue healing and regeneration.
In relation to the first aim I have already discussed the importance of this stage and why it should not be a goal to promote inflammation either as this can increase the level of tissue damage, unnecessarily prolonging the repair process. A further aim of managing inflammation is to reduce pain, thus reducing the likelihood of compensatory changes in movement patterns. However, as previously mentioned the use of NSAIDS to reduce pain should be avoided due to its negative effect on the inflammatory process during the initial phase.
The role of dietaryfat can positively influence this process. It is well established that trans fats, omega 6 rich vegetable oils and saturated fats are pro-inflammatory within the body, while monounsaturated and omega 3 fats have the opposite effect. It is also well established that many people have a diet rich in the former, but not the latter. It has also been shown that the ratio of omega 6 to omega 3 is a general marker of inflammation and the higher the ratio in favour of the former indicates higher levels of general inflammation within the body. Therefore, it is important to balance these two fats with an ideal ratio being close to 1:1. This will not only have a positive effect on injury-related inflammation, but general health as well. I would generally recommend an equal divide of saturated, mono- and poly-unsaturated in the diet. However, in the very acutephase it is prudent to reduce the amount of omega 6 rich (typically vegetable based) oils even more in favour of omega 3's, particularly good quality fish oils. Research has shown this increases collagen deposition and supports healing. While the optimum daily amount of fish oil recommended has yet to be determined researchers have suggested somewhere in the range of 3-9g per day.
Additionally, there is evidence that increased nut, seed and olive oil (all rich in mono-unsaturates) consumption can reduce inflammatory markers.
So in practical terms, what does this mean? Increase your intake of olive oil, mixed nuts, avocados, ground flax seed or flax oil, and other seeds to help balance out your fats. Also ensure you balance out your omega 6:3 ratio by taking the recommended amount of fish oil and reducing or cutting out completely the consumption of the following oils; corn, sunflower, safflower, rapeseed, soybean etc.
As well as the roleof dietary fat, there are a number of phytochemicals and herbs that can play a positive role in management of inflammation and promotion of healing.
Turmeric and its active ingredient curcumin is anti-inflammatory and promotes wound healing. This is widely used in the making of curries, but could easily be added to other sauces. If consuming turmeric extract the recommended dose is 400-600mg three times per day.
Garlic consumption can have dual benefits, it has been shown to inhibit the activity of inflammatory enzymes and positively impact macrophage function. While consuming garlic will have some benefit, to gain more measurable effects it may be required to take garlic extract. It has been recommended to ingest 2-4 cloves a day or 600-1200mg of extract.
Pineapple contains the anti-inflammatory ingredient bromelain. Also known for its digestive and analgesic properties, 500-1000mg doses of bromelain extract daily have been shown to have a positive anti-inflammatory effect.
Boswellia tree extract also inhibits inflammation by inhibiting the effect of enzyme and cytokine activity with doses of 300mg thrice daily.
The flavanoids found in fruit, vegetables, legumes, cocoa, tea and red wine are more widely known for their antioxidant properties, but they can impart a positive effect on inflammation and it is thought this is due to their effect on cell signalling. While the consumption of foods containing flavanoids will help manage the inflammatory stage, it may be required to take nutritional supplements to impart an increased anti-inflammatory effect. These could include; blueberry, grape, citrus or tea extracts or the bioflavanoids quercetin/dihydroquercetin and rutin.
While all of the above herbs and phytochemicals can positively ameliorate inflammation it should be remembered that it should never be the intention to stop this process occurring altogether, but merely to help manage it and therefore, it would not be recommended to take them all at the same time or over consume them, especially in the very acute phase. Their use would probably be more recommended in the management of chronic inflammation or in the subsequent secondary stages of injury repair to speed up healing and prevent chronic inflammation developing. So in conclusion for acute inflammation it is probably best just to include some tea, blueberries, pineapple, garlic, turmeric/curry or cocoa containing products in your daily diet and leave the more aggressive strategies for the other scenarios.
Calorie, macronutrient and micronutrient requirements during recovery
Injury, depending on severity, can significantly affect dietary requirements. Sport and exercise require an increased energy demand. Athletes who do not consume enough food (more prevalent in females) can increase their risk of injury, especially from stress fractures and injuries to ligamentous structures. So while too few calories can increase the likelihood of injury in the otherwise healthy, it can also adversely affect the recovery process and increase the period before a full return to training can take place. Acute injuries also cause an increase in energy demand. Basal metabolic rate (BMR) can increase by 15-50% depending on the severity of the trauma, with sports injury and minor surgery at the lower end and major surgery at the higher end of the spectrum. Therefore, when determining the energy requirement during recovery from injury this increased requirement needs to be considered.
In practical terms, what does this mean? Two factors need to be considered; the nature of the injury and its impact on ability to train. The number of calories one consumes should always based on need and therefore, if different circumstances arise, then adjustments need to be made to account for these changes. Let's look at some examples. If we take a sedentary individual, they will most likely require a calorie intake of BMR multiplied by approximately 1.2. An athlete who trains daily and competes may require an intake of BMR multiplied by approximately 1.7. If for example, this athlete suffered a fairly serious injury and this completely curtailed their ability to train then this would require a reduction in need and a calorific value of BMR x 1.2 + 20%. If the athlete had suffered a severe lower limb injury, but was still able to train upper body then requirement might be more in the region of BMR x 1.5 +20%.
Regardless of the individual scenario, while energy demand may change, athletes should ensure they stick fairly closely to their other dietary habits with regard to number of feeds, the recommended protein intake and adequate macronutrient intake, etc. Following the supplement advice discussed above supplement intake may change slightly during the duration of the injury and then return to normal.
With regard to macronutrient intake, protein should remain fairly high, so aiming for at least 1g per lb bodyweight. Dietary fat has been discussed above, so follow those recommendations in terms of balance of fats. As for daily amounts, aim for around 0.5g per lb bodyweight. With carbohydrate intake there may be a slightly reduced requirement due to a reduction in activity, but they are still necessary for injury healing. The foods eaten should follow the normal healthy guidelines athletes routinely follow, so proteins from lean meats, eggs and lean dairy, whey protein. Fats as discussed above. Carbohydrates from fruit, vegetables and whole grain, minimally processed sources.
Sufficient micronutrient intake is vital for health at all times, but particularly so during injury. During this time there a number these that are of more significant importance. These include the vitamins A, B, C and D, and the minerals copper, iron, calcium, magnesium, manganese and zinc. Vitamin E has been shown to slow healing, so it is advisable to avoid supplementing with this. It is still unclear as to the exact role these vitamins and minerals play, and whether the supplementation of them is merely to avoid deficiency or whether the ingestion of them offers additional benefits in the injury repair process.
There is some evidence though for vitamins A and C, and copper and zinc. Vitamin A enhances and supports the early stages of inflammation, reverses immune suppression and supports collagen synthesis. It is recommended to supplement with 10000IU or eat foods rich in vitamin A, but not both to avoid toxicity. Vitamin C enhances immune system activity during the inflammatory phase and boosts collagen synthesis. It is recommended to ingest 1-2g per day. Copper is important in the formation of new blood cells and acts in conjunction with vitamin C to aid in the formation of elastin to strengthen connective tissue. Recommended dose is 2-4 mg per day. Zinc plays a vital role in tissue regeneration and repair. Zinc deficiency is clearly linked with poor wound healing and a dose of 15-30mg per day is recommended. All of these recommendations are for the initial 2-4 week window post-injury.
While the evidence for calcium and iron in relation to injury recovery has not been established, deficiency in these minerals can lead to increased risk of stress fractures. Therefore, ensuring sufficient dietary intake of calcium and iron is important for long term injury prevention.
Additional supplements that may be beneficial to recovery
There is evidence that the amino acids arginine and glutamine, and the amino acid metabolites ornithine (from arginine) and HMB (from leucine) can produce a powerful and positive effect on injury healing.
Arginine is thought to stimulate the action of insulin and IGF-1, and thus protein synthesis and collagen deposition. It is also thought to stimulate nitric oxide production and therefore blood flow, and activate macrophage activity. Macrophages aid the production and activation of growth factors, cytokines, bioactive lipids and proteolytic enzymes, which all play important roles in the healing process. Quite high doses of up to 30g have shown to be most effective.
Glutamine has been shown to be essential in the metabolism of rapidly turned over cells like lymphocytes and enterocytes. This is particularly so in the case of severe trauma and glutamine supplementation has been shown to reduce the length of hospital stay in patients in this circumstance. However, glutamine and the positive role it may play in wound healing is merely speculation at this time. Although one study that combined it with arginine and HMB did show an increase in collagen synthesis.
In the case of ornithine, because there have been positive results shown with arginine, it has been speculated that since ornithine can be converted to the amino acid proline, which is essential in collagen deposition, it will produce similar effects. Indeed, studies administering ornithine in doses of 20-30g per day have been shown to reduce healing time, increase the strength of injured tissue and increase nitrogen retention (important in muscle repair).
HMB has been shown to inhibit muscle catabolism and increase net protein balance, potentially leading to an increase in muscle mass. It has also been shown to increase collagen deposition and nitrogen balance.
However, some caution should be shown when interpreting some of the results involving these amino acids. Similar to the case with vitamins and minerals much of the research on amino acids has been undertaken with elderly or hospitalised patients who are often malnourished and any supplementation may have merely addressed nutrient deficiencies in those concerned. This doesn't necessarily discount all the research, but it may not have the same effects in a more athletic population, despite the fact that nutrient deficiencies can also occur in this population.
On balance, combining arginine, glutamine and HMB (7g, 7g and 2.5g respectively twice per day) will still likely increase collagen synthesis/deposition, preserve muscle mass and improve healing.
For joint injuries there is some evidence that glucosamine, chondroiton and hyaluronic acid can help with long term pain and inflammation. However, they do not appear to have any benefits for acute muscular injuries.
Soft tissue injuries, regardless of type and severity follow a set phasic pattern. No matter how many precautions you take, injuries are a fairly likely occurrence in sport and exercise. When they do happen you want to be able to get back to activity as soon as possible. Nutrition is certainly one way of helping to speed up this process. By making slight alterations to your diet (many of which should be part of your practice already) and supplementing wisely (based on the best available evidence) then that goal can become a reality.