What do M&S Percy Pigs, fruit jelly, sesame brittle and bone broth have in common and why should you be interested ?

A couple of years ago I noticed that many sports nutritionists, particularly those working elite endurance athletes were including M&S Percy Pig jelly sweets within their diet and provision sheets. The reason for this was that they contain pigs gelatin and studies have linked gelatin to improved musculoskeletal strength and recovery from injury.

Injury risk, Joint Health and Performance

One of the only things that accurately predicts whether someone selected as a promising junior becomes a successful senior athlete, is their ability to avoid injury. Musculoskeletal soft tissue injuries, strains and sprains, are the most common problems suffered by athletes, accounting for around 70% of all sports injuries (Feeley et al., 2008, Hawkins et al., 2001). Similar injuries are also a major problem as you age, often resulting in considerable and lasting discomfort and a gradual loss of mobility (Gheno et al 2012). Anything that can lower the risk of this type of injury is really beneficial and so this has been a focus of research both in public health and sports nutrition.

Injuries to tendons, ligaments and cartilage often result from structural changes to or weakness within the extracellular matrix. The extracellular matrix is the network of molecules surrounding the cells that provides structural and biochemical support (Theocharis et al (2016). Until recently this matrix was considered to be an inert gel, with the sole purpose of feeding and holding the tissues together but it has been discovered it is essential both enabling the muscles and tendons to transmit force quickly and at the same time allowing the cartilage, ligaments, and bones to absorb the force of impact. A healthy extracellular matrix is essential for both optimal performance and injury prevention.

The structure of the extracellular matrix is determined by the amount of collagen and the water stored within the tissue. The stiffness or strength of the collagen is dependent on the number and type of cross-links binding the collagen proteins together. The strength and type of cross links can be regulated by diet and exercise (Baar 2015), which means it should possible to lower injury risk and promote recovery after injury by improving the structure of your extracellular matrix.

Exercise – the theory

Tendons and ligaments are more like bone in the way they respond to exercise. Whereas muscle will continue to adapt all the time it is active (Baar, 2009), generation of connective tissue cells is initially unregulated by exercise but only for approximately 10 min after which they become inactive and unresponsive to exercise for up to 6 hours (Paxton et al., 2012) ie connective tissue becomes stronger when it is exercised intermittently. A second interesting thing about connective tissue cells is that neither the load (Heinemeier et al., 2007) or intensity (Baar, 2017) of exercise matters. Even small range-of-motion exercises with very light weights have been found to increase collagen synthesis and connective tissue function (Paxton et al., 2012) and there is no advantage of strenuous effort. Repeated short periods of light activity that load the connective tissue followed by long periods of rest boost connective tissue strength and recovery.

Nutrition – the theory

This area is very new and there has not been a lot of research. Supplementation of gelatin with vitamin C has been shown to improve collagen synthesis in engineered ligaments (Paxton et al., 2010) and feeding gelatin to athletes has increased collagen production and improved recovery times after injury (Shaw et al 2017, Baar 2017). Collagen supplementation has been shown to thicken cartilage in osteoarthritis patients (McAlindon et al 2011), improve lower knee pain (Clark et al 2008) and help prevent sarcopenia (Rondanelli et al 2015).

Gelatin is made from animal connective tissues and is high in all the necessary amino acids to make collagen. Although the core collagen in a tendon or ligament is set from puberty onwards (Heinemeier et al 2013) it is possible to increase their size and strength in a similar way to the growth of a tree, increasing size by adding bands of growth and so strength but this needs the right building blocks to be present. The main amino acids in collagen are glycine, proline and hydroxyproline. Both glycine and proline are considered to be conditionally essential, meaning that although they can be made within the body from other amino acids this conversion is often not adequate to provide all that is needed, particularly when under stress. The ability to make collagen is also known to be reduced as we age.

Gelatin is made from animal connective tissues and is high in all the necessary amino acids to make collagen. As blood flow to tendons and ligaments is low, essential nutrients are thought to flow into the tissues with fluid, flowing in as the tissue relaxes and moving out as the tissue contracts. This is increased during exercise which means that the best results may be obtained if all the key nutrients needed for optimal extracellular matrix composition and connective tissue growth are present whilst exercising boosting delivery to the soft tissue (Baar 2015).

There has not been any published research specifically on the effect of eating Percy Pigs and although they contain both vitamin C and gelatin, the amount of gelatin is low. The precise amount isn’t given but the 5.3g of protein per 100g suggests there is less than ½ a gram per pig. The doses used in supplement trials have been 10-15g.

What to do…..

To improve the structure of the extracellular matrix and strengthen or repair tendons, ligaments and cartilage you need to introduce a specific exercise session focused on them. This should be a short period of loading (just 5 or 6 minutes) that targets the tendons/ligaments/cartilage that you want to focus on. This may be something like skipping, step-ups, repeated sitting/standing, ankle raises or rotator cuff exercises depending on the area of concern. This short session should be performed at least 6 hours away from other exercise, particularly intense exercise. The aim should be to stimulate extracellular matrix collagen production where needed and so promote soft tissue strength or boost recovery and so lower the likelihood of repetitive stress injuries.

As nutrient delivery is key and improved during exercise, it is beneficial to have all the nutrients available to the tissues. The protocol used in the studies by Shaw and Baar was a 15g dose of gelatin taken with 50mg of vitamin C, one hour before the exercise session. The simplest way to do this is to add 15g of gelatin to 200ml (40ml cordial) of hi-vitamin C squash (eg Ribena) and to drink it before allowing it to set. 200ml of Ribena contains ~60mg of Vitamin C. Or you can make jelly sweets by adding 7 sachets (84g) gelatine (eg Dr Okter) to ~150ml fruit juice / purée and setting in an ice tray. An adaptation of the recipe used by Baar et al is given below the references.

In sports exercise research the number of individuals involved in a study can be low and as this is a new area of research much of the knowledge comes from animal studies or lab tests. In other areas of nutrition it is often the case that supplementation is effective only where there is a deficiency and there can be responders and non-responders to a protocol. As glycine and proline are conditionally essential, collagen production is less efficient as we age and our diets probably contain less gelatin or collagen than anytime in history, I think it is worth ensuring that foods containing gelatin or collagen, or are good sources of the underlying amino acids or promote collagen production are included within the base diet. Bone broth is made by boiling down animal or fish bones in water to make stock, when it cools the liquid gels as it contains gelatin. The amount will not be as great as consuming sheet gelatin but it is a good natural source of collagen and animal studies have shown that eating foods rich in collagen/gelatin over time have a greater effect on musculoskeletal collegen synthesis than supplementing the underlying amino acids (Oesser et al 1999). Good vegetarian options include spirulina, Aloe Vera (which also may promote collagen production (Surjushe et al 2008)) and sesame seeds.

REFERENCES

Baar, K. (2009). The signaling underlying FITness. Appl. Physiol. Nutr. Metab. 34:411-419.

Baar, K. (2015). Training and Nutrition to prevent soft tissue injuries and accelerate return to play. Sports Science Exchange 28(142), 1-6.

Baar, K. (2017). Minimising injury and maximising return to play: lessons from engineered ligaments. Sports Medicine 47 (suppl 1), 5-11.

Burr, D.B., A.G. Robling, and C.H. Turner (2002). Effects of biomechanical stress on bones in animals. Bone 30:781-786.

Feeley, B.T., S. Kennelly, R.P. Barnes, M.S. Muller, B.T. Kelly, S.A. Rodeo, and R.F. Warren (2008). Epidemiology of National Football League training camp injuries from 1998 to 2007. Am. J. Sports Med. 36:1597-1603.

Gheno R, Cepparo JM, Rosca CE, Cotten A (2012). Musculoskeletal Disorders in the Elderly. J Clin Imaging Sci 2: 39-43

Hawkins, R.D., M.A. Hulse, C. Wilkinson, A Hodson, and M. Gibson (2001). The association football medical research programme: an audit of injuries in professional football. Br. J. Sports Med. 35:43-47.

Heinemeier, K.M., J.L. Olesen, F. Haddad, H. Langberg, M. Kjaer, K.M. Baldwin, and P. Schjerling (2007). Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types. J. Physiol. 582:1303- 1316.

Heinemeier, K.M., P. Schjerling, J. Heinemeier, S.P. Magnusson, and M. Kjaer (2013). Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb 14C. Faseb J. 27:2074-2079.

McAlindon, TE. Unite, M. Krishna, N. Ruthazer, R. Price, L.L. et al (2011). Change in knee osteoarthritis cartilage detected by delayed gadolinium enhanced magnetic resonance imaging following treatment with collagen hydrolysate: A pilot randomised control trial. Osteoarthritis and Cartilage 19(4), 399-405.

Oesser, S. Adam, M. Babel, W. et al (1999). Oral administration of (14)C labelled gelatin hydrolysate leads to an accumulation of radioactivity in cartilage of mice (C57/BL) J Nutrition 129:1891-1895.

Paxton, J.Z., L.M. Grover, and K. Baar (2010). Engineering an in vitro model of a functional ligament from bone to bone. Tissue Eng. Part A. 16:3515-3525

Paxton, J.Z., P. Hagerty, J.J. Andrick JJ, and K. Baar (2012). Optimizing an intermittent stretch paradigm using ERK1/2 phosphorylation results in increased collagen synthesis in engineered ligaments. Tissue Eng Part A. 18:277-284.

Rondanelli M. Perna S, Faliva MA, Peroni G, Infantino V and Pozzi R (2015). Novel insights on intake of meat and prevention of Sarcopenia: All reasons for an adequate consumption. Nutr Hosp 1:32(5):2136-2143

Shaw, G. Lee-Barthel, A. and Baar, K. (2017). Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr 105: 136-143

Surjushe A, Vasari R, Saple DG. Aloe Vera: a short review. Indian Dermatol 53(4):163-6.

Theocharis, A., Skandalis, S., Gialeli C., Karamonos N., (2016) “Extracellular matrix structure” Advanced Drug Delivery Reviews 97: 4-27

RECIPE (8 servings)

80 grams gelatin

1 cup of water

2 cups fruit juice or purée

500mg vitamin C (certified for sport ascorbic acid)

DIRECTIONS

1. Bring fruit juice / fruit purée to the boil

2. Mix gelatin and vitamin C into water (room temperature)

3. Add boiling fruit mix to the gelatin/vitamin C

4. Pour onto a flat plate or into silicon ice or jelly moulds (if not using silicon oil lightly).

5. Put into the fridge