Are you exchanging your hard-earned money for a multivitamin which provides little to no benefit? You can't receive any benefit from a supplement if it's not being absorbed...one of the first qualities a multivitamin must have in order to be effective. Do you know if the nutrients in your multivitamin are being absorbed? This seems to be an appropriate question since the U.S. is spending somewhere around $22 billion a year on dietary supplements, of which a considerable portion is tied to multivitamins.
The absorption of a multivitamin is often an overlooked factor when comparing supplement brands. But, it has major implications for the effectiveness of a supplement. The listed levels of nutrients on a multivitamin label are in no way an indication of how much actually make it into your bloodstream for use in the body! This is exactly why you want to seek out high quality, or pharmaceutical-grade, multivitamins.
Multivitamins that are manufactured to pharmaceutical standards are formulated to allow much higher levels of absorption than cheaper, mass produced vitamin and mineral products. This is due to the fact that they are science-based, use more sophisticated manufacturing processes, and adhere to higher quality standards. This is one reason why they cost more (but work better!)
So let's talk about some of the factors that can affect the absorption of a multivitamin (or what is referred to in the nutritional world as "bioavailability"). Several factors can affect the bioavailability of vitamins & minerals in the human body:
* Age
* Time of day multivitamin is taken
* Taking a multivitamin on a full or empty stomach
* Digestive system integrity
* Overall state of health
* Disintegration time
* Dissolution percentage
* Types of excipients used
* Nutrient forms, and
* Interactions with drugs.
As you can probably tell from the factors above, bioavailability can be a complicated topic because it is not dependent solely on product formulation.
Nevertheless, the point I want to make is that A SUPPLEMENT LABEL GIVES YOU NO IDEA OF THE ABSORPTION OF EACH NUTRIENT! (NOTE: It should seem reasonable, then, that stating an overall absorption rate on a package or in advertising can be misleading. So watch for this when choosing a supplement!)
Before discussing each of these factors in detail, let's provide a definition for bioavailability.
Bioavailability is defined as the degree and rate at which a compound is absorbed into a living system or is made available at the site of biological activity. One of the first things to understand about the bioavailability of nutrients is that different vitamins and minerals inherently have different absorption rates regardless of whether they come from a tablet, liquid, powder, or food. Calcium has a relatively standard absorption rate between 25 and 35%. Boron, molybdenum, and iodine can be absorbed at over 90% (when obtained from food sources). And the average absorption rates of zinc, copper, and selenium can range from 30 to 80% (when obtained from food sources). The delivery form (via tablet, liquid, powder, or food) does not generally make a significant difference if an individual is healthy and intakes are adequate. However, a well-made tablet provides a very effective delivery system and is the chosen form of most quality multivitamins and pharmaceutical medications. Tableted products allow for a higher level of active ingredients - almost 3 times as much as a capsule and much more than a liquid or spray. In general, the stability of tablets is also superior to liquids.
So let's discuss the factors we mentioned above that affect the bioavailability, or absorption, of a multivitamin.
AGE:
Age is a factor that can influence the absorption of nutrients. It is true that the ability to absorb nutrients declines as we age, but don't discount the importance of a mulitivitamin. This makes a multivitamin even more critical. Incidentally, a multivitamin should be added at about one year of age to help a child achieve all of the nutrients they need to be healthy. Nutritional needs begin to change during adolescence and then again as we become adults. So a multivitamin is needed through all stages of life.
TIME OF DAY MULTIVITAMIN IS TAKEN:
For purposes of increased absorption, you should always take multivitamins with meals.
Additionally, mineral flux in and out of bone is generally more active while at rest and some very sensitive individuals may notice a slight relaxation effect from taking mineral supplements. On the other hand, some individuals feel that some vitamins provide heightened energy, and claim they have trouble sleeping if they take them too late in the evening. Both claims are, unfortunately, difficult to explain with clinical evidence and should not be noticeable by the general population. Vitamins do not contain any stimulants and do not provide direct energy. Similarly, minerals do not contain sedatives or characteristic effects significant enough to cause drowsiness.
Having said this, perception is often quite powerful and even if there is no plausible scientific explanation, there may be individuals who need to adjust their supplement use accordingly. If you experience changes in sleep or energy patterns, try one of two things: Start with a half-dose and gradually work up to a full dose, or take the tablets at a particular time of day (morning for vitamins, evening for minerals) to minimize any effects on energy and/or sleep.
TAKING A MULTIVITAMIN ON A FULL OR EMPTY STOMACH:
For better absorption, there are several reasons it can be beneficial to take multivitamins with food or a complete meal. One reason is to buffer the stomach (especially important for those with sensitive stomachs). Another reason is to increase the consistency of taking a multivitamin. Many people find it easier to form a habit of taking supplements alongside a meal, as opposed to taking them separately. But perhaps the best reason to take supplements with a meal is that some nutrients (e.g. fat-soluble nutrients like vitamins A, D, E, and K and calcium) typically have improved absorption when taken with a meal or snack.
DIGESTIVE SYSTEM INTEGRITY:
Our digestive system degrades with age and some people just have difficulty with digestion period. In these cases, it may become more difficult for our bodies to absorb nutrients. So our digestive system can hinder the absorption of important nutrients.
To aid in digestion, there are supplements called digestive enzymes that can supply supplemental enzymes to help break down dietary carbohydrates (including sugars and starches), fats, and proteins. These encourage more complete digestion and absorption of nutrients. In addition, there are supplements called probiotics which contain healthy bacteria to help promote healthy digestion. Probiotics also help to improve absorption of nutrients in the gastrointestinal tract.
OVERALL STATE OF HEALTH:
Those who are in a poor state of health and are currently deficient may have significantly enhanced absorption rates for certain nutrients. Also, people whose nutrient needs are greater, such as growing children, pregnant or lactating women, may experience enhanced absorption rates.
DISINTEGRATION TIME:
Disintegration refers to a tablet’s ability to break apart and fragment into small particles in order to distribute the contents - a rather important thing that we all just assume will happen. Tablets that are formulated to meet higher quality standards than is required by law, such as United States Pharmacopoeia (USP) standards, require full disintegration within 30-45 min. If a tablet doesn't disintegrate within this period of time, it has little chance of getting absorbed. Look for something similar to the following statement before purchasing a multivitamin: "Laboratory tested, quality guaranteed. Meets USP specifications for potency, uniformity, and disintegration where applicable."
NOTE: The USP is a non-profit organization that works closely with the Food and Drug Administration (FDA), the pharmaceutical industry, and health care professionals to establish authoritative standards. These standards are enforceable by the FDA and the governments of more than 35 other countries, and are recognized worldwide as the hallmark of pharmaceutical, or advanced, manufacturing quality. Look for a nutritional supplement company that voluntarily adheres to a rigorous quality assurance program modeled after the pharmaceutical industry. This high standard of manufacturing separates top dietary supplement companies from mediocre companies.
DISSOLUTION PERCENTAGE:
Even if disintegration has occurred, it doesn’t mean that the ingredients have dissolved! Dissolution refers to the ability of a supplement to dissolve in solution. (It is expressed as a percentage.) Supplements which dissolve most rapidly have the greatest absorption because nutrients have a limited and defined region of absorption in the gastrointestinal tract. A tablet can have fast disintegration time yet be biologically unavailable i.e. the ingredients can’t get in to do their job. Tablets that are formulated to meet higher quality standards, such as USP standards, are required to dissolve. Dissolution is necessary for a tablet or supplement to be absorbed.
TYPES OF EXCIPIENTS USED:
Excipients (or inactive ingredients) are ingredients used to convert active compounds into dosage forms suitable for administration. All pharmaceutical or nutritional products - whether they are tablets, capsules, or liquids - contain excipients, regardless of whether they are specifically labeled as such. It is simply not possible to formulate tableted products without using binders, coating agents, and/or disintegrants, as well as processing-specific excipients like lubricants.
Interest in the physical effects and properties of excipients used in pharmaceutical formulations has increased in recent years as pharmaceutical scientists have become increasingly aware of the fundamental effects excipients can exert on absorption, stability, and overall performance of a product. Small variations in physical properties of an excipient can produce significant differences in the behavior of a finished product. In other words, using top quality excipients (inactive ingredients) is as important as using top quality active ingredients.
NUTRIENT FORMS:
Nutrients can exist in more than one chemical form, and different forms result in different levels of absorption. Along these lines, a common misconception is that "natural" vitamins and minerals are extracted from plants in their pure form, making them superior to "synthetic" vitamins and minerals which are made in a laboratory. This is often a misleading distinction.
First of all, it is not possible to extract pure vitamins from plants without considerable and significant processing.
Secondly, the biological activity of a compound has nothing to do with its source and is more determined by its chemical structure. In other words, it usually makes little difference whether the chemical originates from a leafy plant or is synthesized. It is the same compound, regardless. Some vitamin and antioxidant compounds can be efficiently synthesized in laboratories to produce products that are identical in chemical form to those found in nature, and that are extremely pure, equally safe, and often much less expensive than their "natural" counterparts.
Third, some synthetic vitamins are preferentially absorbed over compounds provided by food sources. One good example is folic acid, which is preferentially absorbed and utilized over natural food folates that must go through several conversion processes to be utilized as folic acid.
Fourth, sometimes the natural form is better than the synthetic form. An example of this exists with vitamin E. As well as showing the highest level of biological activity, natural vitamin E appears to be quickly absorbed into human cells, whereas the synthetic forms are metabolized (broken down) and excreted in the urine.
The take home message is this: Vitamin and mineral compounds should be used in the chemical forms, be it "natural" or "synthetic", that are best absorbed and utilized by the body.
And finally, avoid the use of multivitamins that provide minerals in the form of inorganic mineral salts (such as oxides, carbonates, sulfates and phosphates). While less expensive to manufacture, supplements using mineral salts do not appear to provide optimal nutritional value. To increase the absorption of minerals, many manufacturers chemically bond the mineral to an amino acid or organic acid carrier. These chelated minerals are believed to mimic the natural mineral chelates that form during the digestion process. Beyond their reported superior absorption, chelated minerals appear to have lower absorptive interference and better tolerance in the gut than the less expensive mineral salts.
INTERACTIONS WITH DRUGS:
Many medicines interact with vitamins. Some drugs increase or decrease the effectiveness of vitamins, and some vitamins increase or decrease the effectiveness of drugs. Because some drugs and nutrients have similar chemical structures, taking them at the same time fools your body into absorbing or using the nutrient rather than the drug. As an example, take a look at warfarin and vitamin K. Warfarin is a drug that keeps blood from clotting and vitamin K is a nutrient that makes blood clot. Eating lots of vitamin-K rich leafy greens, or obtaining vitamin K from a supplement, counteracts the intended effect of taking warfarin. So you have to be careful when taking drugs and multivitamins together. Your best resource for understanding the interactions between drugs and multivitamins is your pharmacist or physician. These individuals have the training, tools, and expertise to help you make an informed decision.
I hope this information has given you a better understanding of the factors involved in influencing the absorption of nutrients in multivitamins. Since multivitamin supplements are necessary in today's world, it's important you are obtaining the most out of your supplements and not throwing your money away.
For more information on this topic, feel free to send me a message. I will be happy to discuss your questions in greater detail.
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