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Critical Thinking

August 26, 2021

Being Well Informed about Supplements

Thinking Critically about Supplements

Thinking critically about supplements is more reasonable than impulse buying, but doing so is complicated. Choosing healthy food and supplements can be confusing and logic can often be counterintuitive. Thinking & reading critically requires some mental and emotional energy. It means we need to try to look beyond persuasive packaging to understand the reasons for a claim and evaluate if it holds up.

The point of this article is not to tell you what is true, but rather to clarify the process of thinking for yourself. I will also give examples of ways that Flora strives to make it easier to make safe and informed choices when choosing a nutraceutical.

What is Critical Thinking

Critical thinking is a questioning method for evaluating evidence to come to our own valid conclusion. We can apply this approach when we read or hear statements or arguments. It means we cannot passively accept the conclusions of those we think are smarter than we are, just because they appear confident. Rather we need to get to know our sources and decide if we can trust them.

Asking deep probing questions before we accept any ideas allows us to better trust our knowledge. Socrates believed that we shouldn’t depend upon the opinions of others, since authority figures can be confused or irrational. And, experts conveying information may be biased or may share conflicting information.

We should not only be provided with conclusions, but support or justification for those conclusions. This applies even to the things we tell ourselves. People are often mistaken about their own conclusions. Feeling ill after a huge ice cream or milkshake could be due to lactose, or perhaps, just too much sugar and fat. Frustratingly, just because a line of reasoning is intuitive doesn’t mean it’s correct. It is also true that even though two things occur together often, does not mean that they will necessarily always occur together.

Reading Critically

It is not adequate for a blog post to be convincing; it should provide evidence. This evidence will be presented as a premise. A premise is used to draw us to the conclusion and gives the reason for a conclusion’s legitimacy. The validity of a conclusion must come from its proof or premises. A false or invalid premise isn’t true and doesn’t support the conclusion.

There are clues to find the premises in an article. I often use phrases such as “a study has shown that…” or “according to a recent study” to indicate the introduction of a premise. Finding the premise may be more difficult when a conclusion comes first and premise after, but the premise is information that can be accepted as true.

Logical Flaws or Fallacies

When listening and reading critically, the aim is to avoid getting sucked into flawed logic. Recognizing flawed logic in arguments depends on evaluating the validity of premises.

Problematic statements with errors in reasoning are called logical fallacies. Hasty generalizations or isolated anecdotes are fallacies, not quality information. Fallacies with funny names like Cherry Picking and Straw Man can sell us on otherwise weak claims. Learn to spot them; they can be easy or hard to spot. Some common ones in nutrition are listed below.

Straw man:

This is misrepresentation of the facts that lead us to the conclusion, setting up a position that is easy to refute and then assigning it to your opposition. It is easy to conclude that the keto diet is unhealthy if you suggest that it consists of mostly cream cheese, or that the low fat diet is unhealthy “because people eat nothing but cereal”.

Ad hominem:

This Latin term means against the man. It shows up in several ways. For example, it is not logical to project our issues with a person onto the position they hold. Hitler was evil, and he became a vegetarian, but this does not make vegetarianism evil.

Post hoc ergo propter hoc:

Another Latin one. The conclusion assumes that if ‘A’ occurred after ‘B’ then ‘B’ must have caused ‘A.’ “My child took a vitamin and then got sick, so vitamins make kids sick” jumps to the conclusion and ignores possibilities such as viral or food borne illness, an unusual allergy, etc.

No evidence of effect:

This is not a formal fallacy, but it comes up in nutrition arguments all the time. Many confuse the state of having no studies showing effect as the same as having studies showing no effect, but no evidence of effect is not the same as evidence of no effect.

Cherry picking:

Citing supports for a position while ignoring any contradictory evidence does not lead to well informed conclusions. Ignoring hundreds of scientists who stand by the safety and benefits of carrageenan but trusting the one outlier is not sound.

Appeal to authority:

If we claim that something is true because a person of status thinks so, we ignore that authorities can be mistaken. Vegetarianism isn’t automatically the best diet for you just because Einstein supported it.

Sources of Authority

Speaking of appeals to authority, most people report trusting nutrition information from health professionals. But who knows about supplements? Medical Doctors, Doctors of Physical Therapy and Doctors of Osteopathy are required to study pharmaceuticals, and have deep scientific knowledge, but their fields have no minimum nutrition or botanicals education. Registered Massage Therapists get 15 hours of education in a combination of nutrition and botanicals, Chiropractors 100 and Naturopathic Doctors get 402.

Natural health programs cover basic science, but even respected nutrition and dietetic programs don’t cover traditional knowledge of herbs. A Registered Holistic Nutritionist from CSNN, for example studies 1000 hours of science, and 1400 hours on nutrition, vitamins and minerals, but nothing on botanical remedies. A Master Herbalist certified by Dominion Herbal College, however, receives 1200 hours of instruction focused on Herbal Medicine.

Practitioners may acquire specialized knowledge from independent research, but it could also be from incentivised company-supplied educational materials. This information is likely factually true and science-based, but partial or one-sided. In other words, cherry-picked. When they propose a DNA test to you, do they mention that your gene expression can change over time, or that DNA science develops so rapidly, ancestry results may be different between companies and change a few months later?


One motivating factor for this type of incomplete disclosure may be the desire to instil trust with a simple and confident declaration. But beware of hyper-confidence. When using the scientific process, even quality information will not always lead to a reassuring, definitive answer. We should outline whether the conclusion is a strong or a weak one and why, recognizing what the limits or caveats are for each conclusion.

Instead of looking for a distinct true or false, it may make more sense to ask “in what circumstances does this apply, and how much?” or “is it possible there is more nuance to the issue?”. When something is true, the opposite may not be false. It is in fact possible find studies supporting a low-fat diet, and studies supporting a high fat diet. Both may be healthful in their own way, when done right.

It is difficult to conceptualize the intricacies of the human body and the level of interconnectedness between its systems, let alone convey this information to others. Having a science background helps on the one hand, a communications background on the other hand, and few people have a combination of both. We can critique the writers of news headlines, however, even university research lab scientists are known to exaggerate health-related science reports in the flawed hope of getting more attention for press releases.

With dense topics, it is tempting to streamline and even more so if the person streamlining has a less than complete understanding of the topic. Nutrition is extremely complex. Presentation of true but partial information is a common issue. Usually, it isn’t sinister, and sometimes, like with the new Nutrition Facts panels, it is really meant to help. Unfortunately, simplification undermines nutrition science. Too little complexity, just like too much, can make it hard to make good choices.

Assessing a Study

If a study is used as proof, first confirm that the referenced study relates to the argument. You might be surprised to see no correlation. Do the study conclusions support the claim? What dose and form were used? Was it proven efficient, or only safe? Is the study recent? For an understanding of the big picture, dig deeper to see the scope of the research on this topic, and look for consistency between studies over time.

What about study quality? There are many types of studies. (Check out this blog to learn more about scientific studies!)Don’t get attached to case studies or observational studies that suggest causative links that may only be association. Look to see if the study is experimental; is it randomized, is it blinded? Do you have an evidence-based study such as a systematic review or meta-analysis? Each of these and their sub-types has a different confidence value. Extra points if you have a high-quality experimental study, a meta-analysis or systematic review.

Evidence is not the Be-All, End-All

Nutrition research is not well funded, and randomized controlled trials are expensive. We therefore might not find the evidence we want. There is rarely a profit incentive to study food. Food science may be underwritten by industry, so follow the money behind the studies. Many trials have a small number of subjects. Meta-analyses that assess small studies together is one way to improve certainty, but do examine who’s behind them and check for bias in the interpretation of results.

If you have put your thinking cap on while listening to a podcast, you’ve weighed the scientific evidence, detected no logical fallacies, looked for the rest of the story around a supplement and you’re aware of any bias and one-sided presentation of facts, does that mean you are in the clear? Not necessarily. Evidence based science is not infallible.

We all have bias, and it is hard to resist the status quo. Universality is something we hope to see in studies, meaning they apply to many different groups of people. Unfortunately, we really aren’t there. There is lack of representation of female health issues, lack of child subjects and lack of diversity along racial and ethnic lines in clinical trials both among the subjects and the leaders.

It’s important that evidence be recent, because science frequently updates what is accepted as true. It is also important to ask the right questions. For example, is organic food worth seeking out? Good quality meta-analyses show inconsistent nutrient differences between organic and non-organic produce. Yet, a study of nearly 70,000 people showed high organic food consumption inversely associated with overall risk of cancer. Do you discount it as only a prospective study, or only an association? Here, as in many cases, you’ll need to do a cost-benefit analysis.

Even if we have a strong grasp of science, and accurate details, that doesn’t always mean that science can explain things. Medicinal plants used successfully in many traditions have shown their potential for thousands of years, yet science may not understand the power of plant medicines or vitamins. Often compounds proven to work as isolates will be found to have different properties when consumed in food.

How Do We Know a Supplement Contains a Potent Amount of What It Says It Contains?

On that topic, before deciding to take something, we must know what it contains. Products should have third party accredited independent lab testing. However, the test must match the product. ICP (Inductively Coupled Plasma) tests can identify mineral profiles, and for coloured components like flavonoids, Spectrophotometer testing would be called for. GC (Gas Chromatography) is best used for oil soluble and volatile/vapor components, while AA (Atomic Absorption) testing works for any residues.

Organic certification is great, but only applies to things that are farmed. Non-GMO status is important for ingredients that have GMO counterparts, such as corn, soy or potato. For this, DNA barcode testing may identify a whole plant, but is not useful for testing botanical extract supplements. You’ll want TLC (Thin Layer Chromatography) used for herb identification and HPLC (High Performance Liquid Chromatography) for measuring the isolated phytochemicals in standardized extracts.

How Can We Be Sure About Supplement Safety, Efficacy and Quality?

The origins and licensing of a product matters. Flora products are legally licensed for sale in Canada as Natural Health Products. What too few people know is that before getting an NPN number and a listing online from Health Canada on the Licensed Natural Health Products Database, the regulatory review process requires Flora to provide evidence of valid, high-quality scientific and/or traditional evidence supporting claims made by the product and to demonstrate safety, efficacy and quality.

Flora’s Food and Dietary Supplements are also in full compliance with the US FFDCA (Federal Food, Drug and Cosmetic Act) and the FDA’s Dietary Supplement and Health Education Act (DSHEA). All Flora’s claims get scrutinized and their facilities follow Good Manufacturing Practices (GMP) regulations and use the most advanced computer testing equipment. Flora invites the Natural Product Association (NPA] and many other third parties to do regular inspections.

Some of these certifications, such as GMP (for good manufacturing processes) are meant to guarantee quality or protect consumers from product contamination. Yet seeing a certification symbol on a bottle is not always a guarantee. In fact, the Auditor General of Canada found that many GMP facilities do not follow protocols properly.

If someone in your household has a serious allergy, do ensure that you trust your source. Ask the companies you buy from how they are doing their best. Flora, for example, prioritizes following GMP protocol. Flora is constantly assessing and improving. We have a Joint Health and Safety Committee with members that ensure that Flora is doing what we promise. Members carry out monthly inspections and staff interviews, meet to review policies, production procedures, and training.

Personal Biochemical Individuality

Knowing what is right for you is personal. These days, we understand that two people with the same genes will have different gene expression based on lifestyle factors. It has been shown that the accepted glycemic effect of a food is the median or average for a population, but an individual’s reaction cannot be predicted – it may be very high or very low compared to the average. Being in the healthy range for blood calcium levels may be functionally low for person ‘A’ and functionally high for person ‘B’.

When making choices, only you know when you have enough information. To make it easier to get the information you need for yourself and your family, Flora has both a Master Herbalist with a BA in Communications and a flair for clear writing, as well as an RHN with a BA in Political Science (well versed in critical thinking) available five days per week to answer your product related questions by email, phone and elsewhere.


About the Author: Dana Remedios

Holistic Nutritionist Dana Green Remedios, RHN, RNCP has a passion for helping others break through their blocks to greater health, wealth, and happiness, working with transformational mind-body tools. The Vancouver-based educator and coach answers your questions in English, French, and Spanish as a Specialist working in the Product Information Department at Flora, and is a regular contributor to the FloraHealthy blog.

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