Interest in Tryptophan

Tryptophan was discovered by Dr. Frederick Hopkins in 1901. Early research in this area was prompted by health problems resulting from inadequate protein content in turn-of-the-century diets. Many years later, people’s diets had improved to the point where the absence of protein, and hence, tryptophan, wasn’t killing them but another need for increased tryptophan in the system was beginning to be filled. A synthetic equivalent of tryptophan was marketed and by the 1980s tryptophan was available over-the-counter and became a very popular drug. In 1989 the sales of L-Tryptophan supplements (synthetic tryptophan) in health food stores, supermarkets, and drugstores was estimated at US$60 million according to the Council for Responsible Nutrition, a Washington based trade group that represents manufacturers and marketers of nutritional supplement products. According to the New England Journal of Medicine, at its peak approximately 2% of the US population was taking L-Tryptophan. The market success of tryptophan was based on its clinical success in a variety of states including insomnia, anxiety and pain conditions

The FDA banned the use of synthetic tryptophan in the U.S. in 1989 after an outbreak of eosinophilia myalgia syndrome [EMS]. One company in Japan was responsible for a batch of poorly made synthetic tryptophan which led to the deaths of a number of people and consequently, the FDA ban. Natural protein sources of tryptophan were specifically excluded from the ban but it cast a pall over the use of tryptophan which is only now lifting.

Origins of the Zenbev Idea

Over the counter sales of L-Tryptophan were banned in Canada but it was allowed by prescription from a medical doctor. Dr. Hudson used tryptophan in his clinical practice with some success. He was familiar with the benefits of tryptophan and his knowledge of the scientific literature allowed for his appreciation of the need for a carbohydrate to assist tryptophan crossing the BBB.

Many patients complained of sleep and anxiety problems and, not wanting them to become tolerant and dependent upon sleeping pills, Dr. Hudson often recommended tryptophan in pill form. While he described the need to take a carbohydrate with it, avoid other proteins, take vitamin B3 & B6, etc. he found that few people were compliant with these instructions and, more often than not, they returned saying that it didn’t work. Those who did follow these complex instructions found that they experienced significant benefit. This prompted Dr. Hudson to begin to think of a way to deliver the benefits of tryptophan in a simple, dietary manner that didn’t require much fuss or effort.

The “Tryptophan Paradox”

The Tryptophan Paradox effectively eliminated the use of protein source tryptophan as an effective way of building brain tryptophan levels. Natural food source tryptophan does not exist in isolation. Tryptophan belongs to the family of amino acids all of which bind together to form proteins. Protein-based foods vary in how much tryptophan is present. Eating foods rich in tryptophan, however, will not increase your brain tryptophan levels. Here lies the essence of the Tryptophan Paradox: eating protein foods rich in tryptophan will decrease rather than increase your brain tryptophan levels.

The explanation behind the Tryptophan Paradox relates to the Blood-Brain-Barrier [BBB], a shield that protects the sensitive brain from noxious substances that are in the blood. At the same time, nutrients in the blood must be allowed in the brain. In the case of tryptophan, access to the brain happens across a transporter that recognizes the tryptophan molecule and then facilitates its absorption into the brain.

The problem with tryptophan is that it shares this transport site with other amino acids which are far more abundant and better able to “stick” to the transporter. The result is that a high protein food contains tryptophan but also contains many more of the other amino acids that will out-compete tryptophan for access to the brain transporter site. Consequently, when you eat protein foods your blood tryptophan levels go up but your brain levels go down. Competition between tryptophan and other amino acids at the BBB transport site results in tryptophan’s difficulty reaching the brain.

The solution to the competing amino acids problem proved fairly simple in the end but was not obvious in the beginning. The trick was to combine a protein rich in tryptophan with a certain kind of carbohydrate. Through his familiarity with the scientific literature, Dr. Hudson was able to draw upon the groundbreaking research of MIT scientists from the 1970s. The significance of this finding was the key to unlocking the tryptophan paradox.

The addition of a strategic carbohydrate increases serum insulin levels. Insulin, when it is released in the blood, suppresses all amino acid levels, except for tryptophan. It is important that just the right amount and just the right sort of carbohydrate be combined with the protein-source tryptophan. It is the critical combination of gourd seed flour protein and dextrose that led to clinical success.

This is significant in that a functional food derived from these ingredients and tested clinically proved more effective than the drug form of tryptophan without the risk if adverse side effects. This functional food solution which the body recognizes and readily absorbs is also an improvement on classical medications which suppress normal brain chemistry.

Product Development

Since creating a new drug was not an option, Dr. Hudson began to explore the idea of a functional food before this was even a category. His initial thinking was to combine a food source of tryptophan with a carbohydrate and put it together in a food bar. This necessitated first determining the best protein-source of tryptophan. A number of seeds were screened at the Guelph Food Technology Centre and it was determined that the seeds of the gourd variety contained the highest amount of tryptophan (20 mg) per gram of protein. The variety of seed chosen was the curcubita pepo which is commonly known as the pepita seed since it is already in the food chain and widely available commercially.

The protein was further concentrated by a process of cold pressing out the oil which comprises almost 50% of the seed. Organic pumpkinseed oil has many fine qualities but in this case, the oil conflicts with function of the carbohydrate so it is removed. The concentrated protein meal that is left is ground to a fine powder but remains essentially in its intact protein state.

Determining a source of carbohydrate was a little easier. This carbohydrate, however, must be a high-glycemic carbohydrate in order to induce enough of an insulin spike to draw the other amino acids away from the transport sites. An organic dextrose was chosen which is made from corn. A prototype food bar was created but it was determined that a powder would have a much longer shelf life and so product development was steered towards creating a drink mix. The new profile was ready to be introduced in early 2003 for test market purposes. Zenbev in this form was introduced to the Canadian market in the fall of 2004.

The Importance of Light/Darkness

An interesting and unique quality of tryptophan is that it is light sensitive. This means that the tryptophan operates differently in the body depending upon the available light. In normal light conditions tryptophan metabolizes to serotonin and produces a feeling of calmness. Tryptophan will only metabolize to melatonin, and consequently help produce a natural sleep, in the absence of light. It is, therefore, important to ensure that the sleep environment is as dark as possible. If this is not possible, the purchase of a high quality sleep mask is advisable to ensure conditions which maximize the brain’s melatonin production.

The production of melatonin not only contributes to a good night’s sleep but also appears to be a necessity for optimum health. Even low amounts of ambient light will suppress the production of melatonin which will affect not only sleep but has other health consequences as well. Night shift workers, for example, have a significant increase in certain forms of adenocarcinoma such as breast cancer and prostate cancer. Dr. Hudson believes that scientific research is only beginning to come to grips with the protective benefits of adequate melatonin levels in the body.