Saturday, November 22, 2008

Joint Supplements: Good or Bad?

One of the most common questions I am asked is "Do joints supplements work?"

The short answer is that indeed, they do. But like everything, there are complexities that are worth understanding.

First of all, understanding joint hydration is key. Our joint surfaces are lined by cartilage. The Hyaline cartilage that lines the surfaces of the bones derive some of their nourishment from the skeleton for sure, and the rest by imbibing joint fluid (synovial fluid) through a process of being compressed during movement (squeezing out contents) and then being decompressed (absorbing fluids) - sort of like a sponge. This process is normal and occurs with normal joint movements because as the joint moves from one end of the range of motion to the other, it goes through a natural compression and decompression phase with maximum compression occurring at the end of the range and maximum laxity in the mid range.

It is critical for joint cartilage to be hydrated because it is the water content of the cartilage that prevents compression of the cartilage. The chemical properties of water are such that water is not compressible, hence the field of hydrolics! In any event, in a perfect world, cartilage would maintain maximum hydration and joints would never fail. But even the natural flow of liquid into and out of the cartilage during normal movement requires that the cartilage has a mechanism to keep water in the cartilage matrix. Well, the cartilage cell, a chondrocyte, has the solution. Chondrocytes make two products effectively. Fiber to construct the architecture of the cartilage, and the chemical precursor molecules that are extruded into the extracellular matrix. Once extruded, these molecules spontaneously combine to form a long mucopollysacheride called glucoseaminoglycan (GAG).

GAG has an amazing property in that it has a high affinity for water, binding water to the point that it weighs 1000 times more wet than dry. So as long as the cartilage has GAG on board, binding water should occur without difficulty, right? Right. But, here's the thing. As we age, our cells make less GAG and the GAG that is made is of poorer quality and does not last as long. In any event, the half life of GAG is between 1 and 7 days, so continuous manufacture is needed.

This is where nutritional supplements come in. Theoretically, by taking joint supplements, you should be able to provide the cartilage the nutritional support to make more GAG, which leads to reduced joint discomfort and improved range of motion.

Because joint supplements are not a regulated product, the thing to do is to look at the science that supports using these products. For example, you would want to be sure that a. The product can be absorbed. Usually, there are at least two molecules of importance including glucosamnosulfate and chondroitinsulfate, and some studies suggest that the chondroitin is too large a molecule to absorb through the stomach, and injection is required for absorption. So the first consideration is bioavailabilty. b. Once absorbed, the next question is: Does it find its way into the articular spaces? c. The next consideration is this: Does it get absorbed by the cartilage? and finally, d. Does it demonstrate increased cartilage thickness and hydration.

It is important, from my point of view, to understand that if you are going to use a nutritional supplement, you should only do so if there is good science to support its use. Otherwise, you are simply making expensive urine! What is good science? A good research project should have a large study group (the "n"), it should be a double blind placebo controlled study, and the outcome should have statistical significance - which is to say that the outcome occurred because of the molecule (in this case) rather than by chance.

There are such products on the market, but you need to also know that there are other studies that show as much as a 95% variability between what is in the capsule and what is on the label! So another consideration is that you want a product that is manufactured to pharmaceutical standards with little or no variability from capsule to capsule and bottle to bottle due to production.

Additionally, I think it important to realize that cartilage is one form of dense connective tissue, but our tendons, capsules and ligaments are all essentially made of the same stuff as joint cartilage - collagen is the most prevalent protein in the animal kingdom. Its pretty much what we are made of - collagen plus a few specialized cells (like you eye cells, or nerve cells for example). So it stands to reason that our dense connective tissues in general also stand to benefit through the use of joint supplements. Anecdotally, I have seen many people of a certain age (like 45 and up) who have benefited greatly by taking a joint supplement for chronic tendinitis successfully. On the other hand, there is not good evidence that it works in the spine, although anecdotally again, I have had the experience of patients reporting otherwise.

OK, so what do I recommend? I believe that over the age of about 35 or so, active people should use a joint supplement for prevention and to enhance longevity, and the products I recommend are Cosamin DS and alternatively Move Free. Both of these products are of a pharmaceutical grade, and are well supported by excellent science that demonstrate bioavailablity, and increased cartilage hydration and thickness. The one drawback, however, is that they can increase your cholesterol. If you are subject to elevated cholesterol, but you are planing to try joint supplements to help you achieve a greater degree of joint comfort and improved function, you should monitor your cholesterol levels very closely.