Dietary Supplements: What Every Cancer Patient Needs To Know – Part 2

In our previous blog article, we reviewed the issue of supplement purity. Now, let’s consider the issue of supplement potency. When we use the term potency, we’re referring to two things: (1) the strength and freshness of the supplement, and (2) the quantity or concentration of active ingredients. These factors can vary greatly among supplements with ostensibly the same ingredients but different brand names; therefore, the first question you should ask is: Is the main ingredient(s) biologically active and thus likely to confer some benefit? Since potency declines over time, supplement labels should carry an expiration date – a basic measure of quality assurance. They should also carry warnings regarding potential harmful interactions or side effects. Unfortunately, because most companies do not produce supplements designed specifically with the needs of cancer patients in mind, it is rare that these specific concerns are mentioned. This is even more reason that we believe physicians and nutrition experts must oversee, examine, and monitor the formulations they advise for cancer patients, as we do here at the Block Center. All of our supplement recommendations are specific to cancer patients. This is extremely important because the supplements readily available online and on store shelves are designed for wellness care and routinely include growth-stimulating compounds and other agents that cancer patients should avoid.

If you think potency is not a serious concern for supplement users, think again. While some manufacturers provide a chemical analysis of their herbal products – which can give the consumer at least a measure of confidence in their products – there are many supplements available for sale that have inadequate levels of active ingredients, and some that actually contain no active ingredients whatsoever! As a case in point, consider the findings from a study that sampled dozens of different ginseng products. After pooling the results of numerous analyses, the investigators concluded that six out of every ten products were deemed “worthless,” while one in four contained no ginseng at all! (ginseng is among the herbal agents that have shown the potential to have both anticancer as well as stress-reducing – adaptogenic – properties).

A recent analysis of another widely used supplement, St. John’s Wort, was equally concerning. An independent lab that provides test results for a wide variety of readily available health and nutrition products, found that 60% of the St. John’s Wort supplements they tested did not contain the expected amounts of one or more of the essential plant chemicals! In addition, there was an enormous range in the amount of stated key ingredients between different brand-name products.

Ginseng and St. John’s Wort are just a couple of examples of this industry-wide problem. Independent third-party testing has shown that many other agents have also failed to meet the claims stated on their labels. Certainly, the lack of government standards for quality, as well as a lack of regulatory responsibility on the part of the manufacturers both play a significant role in this ongoing problem.

One way that manufacturers can help minimize this issue is by providing “standardized” extracts. These extracts contain specified amounts of particular phytochemicals based on what is scientifically thought to be the optimal concentration. When a supplement is standardized, you can feel more confident that you’re getting what the label says.

Standardization is achieved by several means: by making an extract containing only the phytochemicals that are thought to be effective (active) for a particular condition, by blending herbal extracts; by spiking with the active constituent or by standardizing to what is referred to as a “marker” compound. The marker compound is a phytochemical that is unique to the species of plant that is present in the extract.

By using standardized products, you know with some assurance how much of the active ingredient is actually present in the supplement. And for some ingredients, it is optimal to use products that are high in specific phytochemicals.

In addition to herbs (such as ginseng and St. John’s Wort), vitamins, minerals and specific phytochemicals extracted from foods (such as beta-carotene) are also important supplement constituents. These phytochemicals can also be synthesized chemically instead of extracted from foods. In general, at the Block Center, we lean towards natural phytochemical supplements over synthetic supplements, because the latter may tend to have lower potency or may lack anticancer properties that we feel are important. For example, natural vitamin E contains 8 different phytochemicals, whereas synthetic vitamin E contains only one (alpha-tocopherol, commonly included in commercial multivitamins). But some of the other 7 phytochemicals, such as gamma-tocotrienol, have anticancer properties that alpha-tocohpherol lacks.

Now for some good news! Our awareness of issues of supplement quality is improving. In 2007 the FDA published a set of rules for what are called “Good Manufacturing Practices” for U.S. supplement producers. These rules were designed to get manufacturers to implement procedures such as:

  • Keeping records on individual batches of supplements
  • Using good identification practices
  • Using appropriate equipment
  • Protecting supplements from becoming adulterated
  • Establishing quality control processes

Therefore, it might be helpful to look for a product that has the “GMP” stamp on it. However, even this doesn’t guarantee that the supplement is safe – particularly for cancer patients – or that it’s been third party tested for potency and purity.

In Conclusion:

As we have discussed, when used properly, nutraceuticals can be a powerful tool in increasing the health, treatment benefits and quality-of-life for many patients. Conversely, these products can be seriously problematic when used improperly and without appropriate supervision. This is particularly true if one is fighting a disease such as cancer, as there are many widely available supplements on the market that are not suitable for cancer patients. We strongly recommend seeking the advice and guidance of a healthcare practitioner who is knowledgeable and experienced in the use of nutraceuticals prior to taking them. And, equally important, discuss all of the supplements you are taking with your treating physician.


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