Natural Sugars, Sweeteners, and Thyroid Health

It’s common for people who have thyroid and autoimmune thyroid conditions to have blood sugar imbalances.  Eating a large amount of carbohydrates and refined sugars is the primary factor responsible for this.  However, many people wonder about natural sugars and sweeteners, and so I decided to put together a post which discusses this, including which ones are okay to consume, which ones should be avoided, and which ones are controversial.

One thing to keep in mind as you read this information is that while some natural sweeteners are better than others, regardless of the type of sugar or sweetener, you do want to minimize your overall consumption of these.  Although there are some health benefits of certain sweeteners such as honey and maple syrup, eating large amounts can have a negative effect on one’s health.  This is true not only with the sweeteners I mention here, but even with whole foods which contain larger amounts of sugar, such as fruits.  For most people, eating a few servings of fruit per day is fine, but eating large amounts of fruit on a daily basis can cause health issues in some people.  This is especially true with those who have blood sugar imbalances and/or a yeast or bacterial overgrowth.

I’m not going to talk in detail about fructose in this post, but I wanted to briefly mention it, as when it comes to the different types of “natural” sweeteners, the high levels of fructose in some of these can be an issue.  Of course fruit has fructose, but eating a small amount of fructose won’t cause problems for most people.  On the other hand, consuming large amounts of fructose on a regular basis can impair insulin sensitivity and cause metabolic dyslipidemia (1) (2) (3).  While many people realize that high fructose corn syrup can be detrimental to their health, they might not realize that certain natural sweeteners such as agave syrup also has large amounts of fructose.  Once again, this doesn’t mean you need to completely avoid consuming fructose, but you do want to minimize your consumption of it.

With that being said, let’s go ahead and discuss some of the different forms of natural sugars and sweeteners:

Honey. There are many different health benefits of honey.   Honey consists of mainly fructose and glucose, along with 25 different oligosaccharides, and it has a glycemic index anywhere from 32 to 85 (4).   It also contains small amounts of proteins, enzymes, amino acids, minerals, trace elements, vitamins, aroma compounds and polyphenols (4).  Many studies have shown that honey is more tolerable than most common sugars or sweeteners in healthy subjects, as well as in patients with impaired glucose tolerance or diabetes mellitus (5).  Another study showed that honey caused greater elevation of insulin than sucrose, although it reduces blood lipids, homocysteine, and CRP in normal and hyperlipidemic subjects, and when compared with dextrose and sucrose caused lower elevation of the plasma glucose level in diabetics (6).  However, another study showed that while consuming honey can provide beneficial effects on body weight and blood lipids of diabetic patients, it also raises hemoglobin A1C (7).  Even though honey is high in fructose, most people with thyroid and autoimmune thyroid conditions can have a small amount of raw honey every now and then.

Maple syrup. Maple syrup, along with honey and brown sugar has shown intermediate antioxidant capacity (8).  It has many different phytochemicals, which might lead to numerous health benefits (9).  One study compared the enhancement of plasma glucose levels in type 2 diabetes by oral administration of sucrose or maple syrup, and concluded that maple syrup may have a lower glycemic index than sucrose, which may help in the prevention of type 2 diabetes (10).  Just as is the case with raw honey, many people with thyroid and autoimmune thyroid conditions do fine consuming small amounts of maple syrup every now and then.

Molasses. Molasses can also be used as a natural sweetener, as it the main byproduct of sugar production, and it is high in antioxidants (11).  In fact, one study looked at the total antioxidant content of some of the different alternatives to refined sugar, including raw cane sugar, maple syrup, agave, honey, etc., and found that dark and blackstrap molasses had the highest total antioxidant content (12).  Blackstrap molasses is also a good source of calcium (13).  Small amounts of molasses is fine for many people with thyroid and autoimmune thyroid conditions.

Agave syrup. A lot of people consider agave to be a healthier type of sweetener.  The good news is that agave syrup has a low glycemic index and might contain beneficial antioxidant nutrients, trace elements, or phytochemicals (14).  The bad news is that it is very high in fructose, and depending on the source and how it’s processed, it might actually have higher levels of fructose than high fructose corn syrup.  Consuming agave syrup can potentially lead to elevated serum triglycerides and VLDL (14).  Dr. Joseph Mercola has put together a very interesting and eye-opening article on agave syrup, and explains why you should avoid it.

Stevia. Stevia is a small perennial shrub that has been used for centuries as a bio-sweetener and for other medicinal uses such as to lower blood sugar (15).  It has no calories and is over 100-300 times sweeter than table sugar (15).  Steviol glycosides are the secondary metabolites responsible for the sweetness of stevia (16). One study on diabetic rats showed that stevia consumption not only resulted in a reduction of blood glucose, but also might ameliorate liver and kidney damage (17).  Based on another study on male rats which decreased their fertility, there is a small concern that stevia can have a negative effect on fertility (18).  However, this is yet another controversial subject, and there is no evidence that taking stevia can decrease fertility in humans.  With that being said, if someone is trying to conceive and/or is having a difficult time conceiving then it probably would be a good idea to play it safe and avoid stevia.  In addition, a recent study showed that the stevia glycosides can inhibit the growth of lactobacillus reuteri (19).  This has caused some healthcare professionals to claim that stevia is harmful to the gut flora, although more studies are definitely needed in this area before we can come to such a conclusion.  I’ve had patients with thyroid and autoimmune thyroid conditions consume small amounts of stevia while following a natural treatment protocol without it having a negative effect on their recovery.

Coconut sugar. I have had many patients ask about coconut sugar, also known as coconut palm sugar.  This is lower in fructose than some of the other sugars and sweeteners I’ve listed here.  However, the fructose content is somewhat controversial, as some sources claim that it has less than 10% fructose, while other sources claim it’s closer to 40%.  Coconut sugar does seem to be a good source of certain minerals and inulin.  While inulin can be beneficial to the gut flora, as it can help to stimulate the growth of the Bifidobacteria species (20) (21), some claim that it might cause problems with gut healing.  With that being said, I came across a study which showed that inulin-enriched pasta actually preserves intestinal mucosa barrier functioning and might be used in the prevention of gastrointestinal diseases and metabolic disorders (22).

Luo han. This comes from a Chinese plant, and is minimally processed.  One study conducted on rabbits showed that it not only improves the lipid profile by lowering total cholesterol and triglyceride levels while increasing HDL-C, but it also lowers plasma glucose levels (23).  Another study showed that Luo han can provide a positive health impact on stimulating insulin secretion (24).  Another study showed that Luo han might be beneficial as an antibacterial agent (25).  Small amounts of Luo han are probably fine to consume.

Xylitol and other sugar alcohols. Xylitol is a naturally occurring alcohol found in plants, and is a common sugar substitute.  Xylitol does seem to have some health benefits, as there is evidence it can help with otitis media (26), and also might help to prevent dental cavities by inhibiting the growth of several strains of mutans streptococci (27) (28).  Erythritol is another type of alcohol and also was found to prevent dental caries.

However, some people experience gastrointestinal discomfort and sometimes even diarrhea when consuming sugar alcohols such as xylitol.  A few studies have shown accelerated intestinal transit after xylitol ingestion (29) (30).  Since sugar alcohols are fermented by gut bacteria,  someone with a condition such as small intestinal bacterial overgrowth (SIBO) will want to avoid all sugar alcohols.  There is some concern that some sugar alcohols might cause an increase in intestinal permeability (a leaky gut), although I wasn’t able to find any studies showing this to be the case.  For those who have dogs you will want to make sure that they don’t ingest any foods which contain xylitol, as there is evidence that acute liver failure can occur when they consume xylitol (31).

Which Natural Sugars/Sweeteners Can You Safely Consume?

Now that I have discussed some of the more common natural sweeteners, I’d like to summarize which natural sugars/sweeteners most people with thyroid and autoimmune thyroid conditions can safely consume, and which ones should be avoided.  As I mentioned in this post, sweeteners such as honey, maple syrup, and molasses seem to be fine in very small amounts.  There is some controversy over stevia, although I personally think that it’s fine for most people to have small amounts of this as well.  However, if someone has problems conceiving then it might be best to avoid stevia.  I recommended to avoid sweeteners high in fructose such as agave since it has high levels of fructose.  Luo han seems to be a safe option.  Although coconut sugar is a better option when compared to certain sweeteners such as agave, it probably is best to first choose honey, maple syrup, or molasses.  Small amounts of sugar alcohols are fine for some people, but they can be problematic for someone with SIBO, and there is some concern that they can cause a leaky gut, although more research needs to be done in this area.

Keep in mind that there are some people who have problems tolerating honey and maple syrup, and if this is the case then of course it’s best to avoid these.  With regards to stevia, if you do take this I would recommend pure organic stevia, and avoid processed types.  But every now and then there will be someone who doesn’t seem to do well even with organic stevia, and thus should avoid it.

In summary, many people with thyroid and autoimmune thyroid conditions have questions about which natural sugars and sweeteners they can safely consume.  Many people with these conditions are able to consume small amounts of honey, maple syrup, and molasses.  In my opinion stevia is also okay to consume by most people, as long as it’s not processed.  Luo han is probably safe to consume in small amounts.  There is controversy over coconut sugar and the sugar alcohols.  And sweeteners high in fructose such as agave should be avoided.