Milk.... The Perfect Recovery Drink?

Athletes of all abilities are looking for marginal gains, for the added extras that will improve their performance. When exploring marginal gains, diet is one of the first areas to look at. And athletes who are spending lots of time training, travelling and competing need to ensure they have a diet that is meeting their nutritional demands. They often turn to supplements as a quick fix to filling any nutritional gaps. Trying to fill these gaps with a natural source will not only be a cheaper approach, but may also be a healthier one, and some natural foods may also provide nutritional benefits beyond those intended.

Milk is one of these foods and may well be a suitable alternative to many sports drinks on the market. In terms of recovery products, there is none better than milk!

What is milk made up of?

Milk is a nutrient dense food containing lactose, proteins, fats, minerals, vitamins and water. Lactose, the major carbohydrate present, is essentially only found in milk. Milk contains a number of specific proteins, but the most common is casein, which compared to other proteins is very digestible in the intestine. Like eggs, milk also provides all nine essential amino acids. Calcium and phosphorous are the major minerals found in milk, and there are relatively small amounts of most other minerals required by the body, including zinc, magnesium, iron and copper. In addition, compared to other beverages, milk contains relatively large quantities of the electrolytes sodium, chloride and potassium. Milk contains varying quantities of many vitamins, including the fat soluble vitamins A, D, E, and K, found primarily in the milk fat.

Milk and performance

Due to issues relating to ease of consumption, the speed of release and the palatability of milk, it is less popular as a sports drink immediately before and during exercise and commercial sports drinks often become the preferred choice. But it's as a recovery drink that milk really comes into its own, and elite athletes often consume bottles of flavoured milk or milkshakes immediately after training or competition.

Post Recovery Nutrition

Many athletes will be familiar with the ‘golden window’, the period 30-60 mins immediately following exercise, during which nutrition can aid recovery. Refuelling correctly during this period is vital to those who may be training or competing more than once a day.

Recovery includes a number of processes, and milk can play a role in all of these:

1. Refuelling the muscle and liver glycogen stores (carbohydrate):

Athletes should aim for around 1g carbohydrate per kg of body weight to help refuel after exercise. Around 600ml of milk will provide 50g of carbohydrate, approximately the same amount as around 500-700ml of a sports drink (depending on the brand).

2. Replacing the fluids and electrolytes lost in sweat:
Athletes should aim to replace around 150% of their sweat lost during the 4-6 hours after training or competition. They should also replace the electrolytes lost in sweat, to ensure that fluids taken on board aren't just excreted in the urine. As well as being 87% water, milk is also a source of sodium, potassium and magnesium, all important electrolytes. Some but not all sports drinks contain electrolytes.

3. Manufacturing new muscle protein, red blood cells and other cellular components as part of the repair and adaptation process:
Early intake after exercise (within the first hour) of essential amino acids from good quality protein foods helps to promote protein rebuilding. Though research into the optimal type (e.g. casein versus whey), timing and amount of protein needed to maximise the desired adaptation from the training stimulus continues, most agree that both resistance and endurance athletes will benefit from consuming 15-25g of high quality protein in the first hour after exercise. Adding a source of carbohydrate to this post exercise snack will further enhance the training adaptation by reducing the degree of muscle protein breakdown. Around 300ml of milk contains 10g of naturally occurring protein and amino acids.

4. Allowing the immune system to handle the damage:
Ensuring adequate carbohydrate stores before exercise and consuming carbohydrate during and/or after a prolonged or high intensity workout has been shown to reduce the disturbance to immune system markers. The carbohydrate reduces the stress hormone to exercise, thus minimising its effect on the immune system, as well as also supplying glucose to fuel the activity of many of the immune system white cells. Milk provides a good source of protein and carbohydrates as well as a number of key vitamins and minerals to enhance the immune system and support overall health.

Milk can play a role in all the key recovery processes, is a naturally occurring product, supplies a number of key nutrients, and is cheaper than many sports drinks and recovery supplements. It could well be the best sports drink available!

Short Days and Long Nights

As the nights get longer and colder, the hours of daylight become shorter, meaning that we see less of the sun and are exposed to fewer UV rays.

This is good news for those that burn easily, but its not just sun tans and sun burn that UV rays are responsible for. They also help produce a large proportion of our Vitamin D requirement as sunlight reacts with a precursor of the vitamin on the skin. Vitamin D deficiencies are becoming more common in athletes, partially due to the precautions taken to prevent skin damage from the sun.

While there is no strong evidence to suggest that Vitamin D deficiency leads to under-performance in athletes, it will have effects on their ability to train and recover and on injury risk. Athletes who are are Vitamin D deficient could be at increased risk of minor illnesses and stress fractures, ultimately leading to interruption in training and competition.

Vitamin D, along with Calcium, Phosphorous and Protein, has a key influence on the growth and mineralisation of bones. It is involved in the absorption of calcium, meaning an athlete could have a really good intake of Calcium within their diet, but if the Vitamin D levels are low, this won't be able to have a positive effect on bone growth and strength.

Vitamin D also has a role in immune function, making it an important nutrient for athletes involved in heavy training. 

Its not all doom and gloom though! Although sunlight is the best source of Vitamin D, small amounts can be taken in through the diet, particularly through fish sources - reiterating their importance within our diet.

Good Sources include:

• Fortified Cereals
• Eggs
• Margarine
• Tuna 
• Sardines
• Mackerel

So why not enjoy training outside and making the most of the daylight we have at the moment, and take advantage of the sources above in our diet. Simple meal ideas include- Jacket Potato or Pasta with Tuna and Sweetcorn, or an Omelet adding lots of different vegetables for variety and added nutritional benefit. 

Nutrition: Fuel for Females

Good nutrition is important for all athletes as they endeavor to fuel their sport, optimise their body composition, and remain healthy.  Nutrition is, however, often of greater concern to female athletes than their male counterparts.  Females naturally have a higher body fat percentage than males and can often become obsessed with dieting.  Societal pressure to conform to a certain appearance, irrespective of body type, as well as pressure from coaches and other support staff, can confound body image issues, and may lead to eating disorders.  Female athletes also carry a greater risk of iron-deficiency anemia than their male and sedentary female counterparts, and must ensure they have adequate calcium intake to prevent against stress fractures and osteoporosis.

Calorie Intake

Females have a slightly lower overall calorie requirement than males, due to their lower muscle mass and smaller body size (on average), but have higher demands for iron, and equal requirements for calcium and some other nutrients.  They, therefore, need to ensure that they eat a variety of nutrient dense foods.

Restriction of calories is a common practice among female athletes, particularly in endurance sports and sports such as gymnastics and diving where a lean physique is deemed desirable, but this is not the best approach to maximising performance.  Calorie restriction can directly and indirectly lead to the female athlete triad, and a lack of nutrients can confound the effect that low body fat and low hormone levels have on bone mineral density.  Women, just like men, need to fuel their bodies.

The Female Athlete Triad

In summary, the Female Athlete Triad, which was discussed in some detail in a previous post, is a trio of inter-related conditions - disordered eating, menstrual dysfunction and low bone mineral density - common in female athletes.  Low energy intake through disordered eating, along with other factors, lead to menstrual dysfunction, which in turn leads to low bone mineral density.  An inadequate diet can also directly affect bone mineral density.  In general, participation in sport and exercise has profound health benefits, but disordered eating, and the absence of menses, can reverse the positive effects of exercise on bone health and other factors.

Pregnancy and breastfeeding

Pregnant and lactating females have greater calorie and nutritional requirements, and those considering pregnancy should increase their intake of folic acid in advance of conception.  Those who are planning to exercise while pregnant should seek advice on both exercise and nutrition.

Iron

Iron is a very important mineral for both performance and general health.  Iron is an important component of hemoglobin which is responsible for transporting oxygen around the body.  Low iron levels will quickly result in poor performance in endurance athletes, but can lead to a number of other health and performance issues, including poor recovery, depressed mood states and reduced immune function. More information on the importance of iron can be found here.

Calcium

As mentioned previously, calcium requirements are as high in females as in males, though dairy products (often the best source of calcium), are often restrict in females trying to maintain a low body weight or lean body mass.  We will cover the importance of calcium and how to ensure adequate calcium in the diet in a future post.  However, it is important to stress that vegans, or those who restrict their diary intake, risk getting adequate calcium in their diet.  Low calcium intake, together with low body weight, is a disaster for bones.

Summary

Females should take special care to ensure that all their nutritional demands are being met.  Iron and calcium intake are particularly important, and special care should be taken if the athlete is vegetarian.  In some cases supplements may be required.  Most importantly, all female athletes should develop a positive relationship with food.  Food is not the enemy.