Thursday, February 25, 2010

Supplements in Soccer – part IV (Caffeine)

Who has never heard of caffeine?? 
Well, probably, nobody!
That’s right, caffeine is a worldwide known substance that is present mainly in coffee, tea, chocolate and cola drinks. Normally, people consume these caffeine sources as a social drink or to keep eyes open in work/school… but did you know that caffeine is also the subject of a huge number of studies on exercise performance (including soccer performance)? That it is actually one of the most scientifically supported substances known to probably enhance your workouts?? Well, indeed, it is!

Effects of caffeine in soccer performance

Caffeine is a mild stimulant that increases the activity of the central nervous system, helping you stay alert and enhancing mental focus. Besides that, caffeine also causes an altered perception of effort or fatigue, so you’ll feel less tired! (Some scientists theorized that it would also cause a glycogen - the fuel of your muscles – sparing by increasing the fat burning, but this effect is short-lived or confined to certain individuals.)

How much caffeine is enough to achieve the desired results?

Small doses of caffeine (such as taken socially) may enhance performance, whereas high doses can be counterproductive to performance. Your target dose must be 1 to 3 milligrams per kilogram (0,5 to 1,5mg per pound), as found recently. This means that if you are a 70 Kg soccer player, you should take 70 to 210 milligrams of caffeine to perform better in the field.
Note that the effects of caffeine supplementation differ between individuals, according to their specific sensitivity and their previous exposure to the substance: if you are an occasional coffee (or other rich dietary source of caffeine) drinker, you’ll tend to be more sensitive to caffeine’s stimulant effects as compared with the daily coffee consumer who has developed a tolerance to caffeine.
Furthermore, you must understand that performance benefits don’t increase with increases in the caffeine dose.  In fact, caffeine doses in excess of 6-9 mg/Kg (approximately 400 -700 mg of caffeine) may cause you a variety of conditions: caffeine jitters, anxiety, stomach ache, bowel transit problems, increased heart rate, impairments of motor control and technique, disruption of sleep patterns and consequent impairment of recovery. As so, acute and long term intake of these large amounts of caffeine is generally discouraged by health authorities.

Table 1 provides you the average caffeine content of common sources.
If you are looking for a specific dose of caffeine, coffee isn’t the best choice when it comes to a well designed supplementation protocol, because of its great variability in caffeine content.

Table 1 - Average caffeine content in common sources. (Reprinted with permission from Nancy Clark, author of Nancy Clark's Sports Nutrition Guidebook, 4 Edition, 2008.)

Advised protocol of supplementation

Caffeine’s stimulant effect peaks in about one hour and then declines as your liver breaks down the caffeine (4 – 6 hours). This is the reason why traditional caffeine supplementation protocols consisted of consuming caffeine 1 hour before exercise. However, similar performance benefits may be seen if you split the initial dose into various doses across the exercise session: for example, take a partial dose 1h before match (ex: a latte) and the rest of it (ex: GU bar) at the interval.

Of course, forget about any protocol of caffeine intake if you don’t eat a balanced sports diet!

Cases where the use of caffeine is discouraged

Those who should abstain from caffeine or limit its consumption are:

  • Smokers;
  • Ulcer patients and others prone to stomach distress;
  • Athletes with anemia;
  • Pregnant women.

What about you? Have you ever supplemented with caffeine? How was your experience? Hope to hear from you!

Recommended reading for more information: 

  • Nancy Clark’s Sports Nutrition Guidebook (
  • Food Guide for Soccer: Tips & Recipes from the Pros   (

Diogo Ferreira, RD
Sports Nutritionist, Lisbon, Portugal
“Promoting best health and performance through nutrition”

Tuesday, February 16, 2010

Supplements in Soccer – part III (commercial sports foods and fluids)

Back to 1967, the Miami Orange Bowl playoff in American College Football saw the Florida Gators in competition against Georgia Tech. The Gators were losing by far and at halftime they were given a new drink, containing electrolytes and carbohydrates, designed for them by Dr. Robert Cade. In the second half, the Florida Gators played well enough to defeat their opponents and win their first Bowl! The drink was released commercially and is still known as Gatorade. This marked the beginning of the sports fuel industry, which is nowadays a billion dollar business with fuels for every possible dietary need and time to eat.

Although these products aren’t absolutely necessary for you to achieve a great performance, sports scientists recognize their benefits as a practical way to meet sports nutrition goals, particularly if you are an athlete who exercises intensely, holds a heavy competition schedule and/or is limited by a sensitive intestinal tract.
Nevertheless, all active people should maintain a foundation of wholesome foods in their day-to-day diets, with engineered choices used to support their exercise programs. In other words, don’t have a sports drink at lunch (instead of a raw fruit juice) or eat a energy bar at dinner (instead of rice or pasta) unless you have no access to common foods. Also, bear in mind that common foods are much cheaper.

I’ll share with you some features of sports foods:

Sports drinks

Sports drinks are designed to provide you an optimum delivery of fluids and carbohydrates during strenuous exercise and also to rehydrate and refuel after the game.

·         Powder or liquid.

·         5 – 8% carbohydrates (200 – 320 Kcal/L);
·         10-35 mmol/L sodium (230 – 800 mg sodium/L);
·         3-5 mmol/L potassium (120 – 200 mg potassium/L).

Energy Bars 

Energy bars are a useful source of carbs (along with protein and micronutrients) to eat at half-time and/or after the game, and might be helpful to supplement the diet of a soccer player who needs lots of calories.

·         Bar (50-60g).

·         40-50g carbohydrates;
·         5-10g/protein;
·         Usually low in fat and fiber;
·         Vitamins/minerals;
·         50-100% of RDA/RDIs;
·         May contain creatine, amino acids.

Sports gels

Sports gels are a useful source of carbs to eat at half-time and/or after the game, and might be helpful to supplement a high carbohydrate diet.

·         Gel, 30-40g sachets or larger tubes.

·         60-70% carbohydrates (approximately 25g/100 calories per sachet);
·         Some contain caffeine or electrolytes.

Electrolyte replacement supplements

These supplements are designed to allow rapid and effective rehydration following moderate to large fluid and sodium losses (ex: after a very intense soccer game where you fail to replace those losses during the match).

·         Powder sachets or tablets.

·         ≤ 2% of carbohydrates (≤ 80 Kcal/L);
·         50-60 mmol/L sodium (1150 – 1380 mg sodium/L);
·         10-20 mmol/L potassium (390 – 780 mg potassium/L).

Liquid meal supplements

Liquid meal supplements are low-bulk meal replacements that may be useful especially to the traveling athlete (portable nutrition). Also, they are suitable to supplement a high energy/nutrient diet during heavy training/competition or weight gain.

·         Powder or liquid.
·          1-1,5 kcal/ml;
·         15-20% protein;
·         50-70% carbohydrates;
·         Low to moderate fat;
·         Vitamins/minerals;
·         500-1000ml supplies RDI/RDAs.

A last advice concerning supplementation with commercial sports foods and fluids: carefully balance pros and cons and ask yourself (or a professional) if you really need that product before buying it. Also, try not to be swayed by a product’s name, because the name might be more powerful than the sports food itself!

Recommended reading for more information: 

  • Nancy Clark’s Sports Nutrition Guidebook (
  • Food Guide for Soccer: Tips & Recipes from the Pros   (

Stay tuned!

Wishing you the best performance ever,

Diogo Ferreira, RD
Sports Nutritionist, Lisbon, Portugal
“Promoting best health and performance through nutrition”

Saturday, February 13, 2010

Supplements in Soccer – part II (multivitamin and mineral supplements)

During my private practice with soccer players, the following case happened: one athlete appeared in my office and told me he needed to take “some vitamin pills”, because he was getting too tired! This belief, common between many athletes, alerts to the need  of a better clarification on multivitamin and mineral supplementation.

Vitamins are metabolic catalysts that regulate biochemical reactions within your body and minerals are required co-factors for function of numerous enzymes in almost every aspect of metabolism and physiology. Roles that directly influence athletic performance include oxygen use, energy generation, hormone function, antioxidant status and muscular contraction.
As so, vitamins and minerals are undoubtedly indispensable to your good health, and because your body doesn’t produce them, you must obtain them through your diet.
However, there is no scientific evidence that soccer players and other athletes need more vitamin and minerals than is recommended for the “average” person.

According to the International Olympic Committee, the best way to get all the needed vitamins and minerals is to eat a variety of foods from all the food groups.

A vitamin and mineral deficiency can really impair your health and performance, but it would take weeks to months of suboptimal ingestion (as can happen in anorexia) to develop such a deficit, because your body has good stores of most of these nutrients.

On the other hand don’t forget that, in general, the more you exercise the more you eat, so you end up ingesting more vitamins too. But caution, this will only happen if you eat a variety of wholesome fruits, vegetables, whole grains, lean meats and low-fat dairy foods, rather than processed foods, refined sugar, too many sweets and treats. Eating vegetable soup on a daily basis and fruit shakes regularly are excellent ways to help you ingest all the micronutrients you need, with the additional benefits of carbohydrates and protein (mostly in shake), fiber and water (mostly in soup).

A lot has been said lately about the benefits of antioxidants for the general population and also for athletes. Although they’re important compounds, consuming high dosages of antioxidants is unlikely to be of real practical benefit and may actually have a pro-oxidant effect (i.e. elevates metabolic stress) which is precisely the opposite of what would be desired.

This way, instead of  taking supplements with antioxidant vitamins (A, E, C and beta-carotene) you may choose the common foods I previously mentioned, making a special effort in the case of fruit (3-5 per day) and vegetables (300-500g per day), because food contains them in the right amounts (as well as other nutrients your body needs).

Cases where vitamin and mineral supplementation may be useful to soccer players and other athletes:

ü  Proven deficiency of any micronutrient;

ü  Weight-loss programs with long periods of energy restriction: athletes ingesting less than 1500kcal per day are more likely to miss their daily micronutrient needs;

ü  Athletes with heavy competition schedule where normal eating patterns may be disrupted;

ü  Athletes who overtrain and eat poorly as a result of being too tired to prepare balanced meals;

ü  Indoor athletes: Futsal (indoor soccer) players, for instance, may be more susceptible to develop a vitamin D deficiency, due to the little solar exposure;

ü  Vegan athletes: individuals who abstain of eating any kind of animal food can develop deficiency on B2, B12 and D vitamins, as well as in protein (macronutrient), iron and zinc;

ü  Food allergies that inhibit the athlete from ingesting important sources of vitamins and/or minerals;

ü  Contemplating pregnancy: female athletes who are thinking of becoming pregnant should take a multivitamin with 400 micrograms of folic acid.

Back to the case I reported initially, there are many reasons for tiredness and given the non-restricted and varied daily diet of this player, a mineral/vitamin deficiency likely had nothing to do with that.
In fact, this soccer player did need to optimize the timing of his before- and after- training/competition snacks and meals (see the post: “Match day Nutrition for Soccer”), as well as respect the importance of getting at least 6-8 hours of sleep.

Recommended reading for more information: 

  • Nancy Clark’s Sports Nutrition Guidebook (
  • Food Guide for Soccer: Tips & Recipes from the Pros   (

Don’t hesitate to ask your questions!
You may leave it in the form of a blog comment or you can contact me directly through my e-mail:

Wishing you the best performance ever,

Diogo Ferreira, RD
Sports Nutritionist, Lisbon, Portugal
“Promoting best health and performance through nutrition”

Monday, February 8, 2010

Supplements in Soccer – part 1

“Sports supplements“, “dietary supplements”, “nutritional ergogenic aids” and “sports foods” are some of the terms used to describe the range of products that collectively form the sports supplement industry. These products normally fit in one of the following definitions:

Ø  They are a practical and convenient way to meet your daily nutrient requirements (e.g. sports bars and gels) or to treat a known nutritional deficiency (e.g. a calcium or iron supplement);

Ø  They contain nutrients or other substances that directly enhance your sports performance.

However, despite all the advertisements, only a few of the commercialized products are scientifically proven to benefit athletes in general and soccer players in particular.
So, before trying any supplement, you must be well aware of the pros (meeting nutritional “needs”, scientifically-proven effects in performance, etc.) and cons (cost, side effects, doping, etc.) it will likely present to you.
Some 7 years ago I committed a mistake many athletes do: I spent lots of money in supplements that I actually didn’t need. In fact I was lacking better training methods, more rest at night and a good nutritional plan made of common foods!!

Thus I strongly advise you to seek professional guidance (with a Sports Nutritionist/Dietitian) before wasting money in useless supplements.
Although there is a time and a place for engineered nutrition, commercial products should be used knowledgeably, at the right times for the right reasons.

Please note that eating a variety of food as close to its natural form as possible is by far the best bet for improving health, preventing disease, optimizing healing, and enhancing performance.
Although these foods seem so mundane, vegetables, fruit, whole grains, lean meats, low-fat dairy foods, nuts, and legumes tend to be better than supplements. They are all rich in a combination of the important vitamins, minerals, fiber, protein, fat, carbohydrate, antioxidants, and phytochemicals that soccer players and other athletes need on a daily basis to succeed on the field.

Therefore, once you apply the best training, resting (6-8h of sleep at night) and nutritional practices to your life, you will be ready to consider supplement ingestion.
In the following blogs I will provide you useful information on a variety of sports supplements.

Recommended reading for more information: 

  • Nancy Clark’s Sports Nutrition Guidebook (
  • Food Guide for Soccer: Tips & Recipes from the Pros   (

Stay tuned!

Wishing you the best performance ever,

Diogo Ferreira, RD
Sports Nutritionist, Lisbon, Portugal
“Promoting best health and performance through nutrition”