Overview

Substantial evidence supports the need to limit sugar intake, leading many people to use alternative sweeteners. These range from natural options like honey and maple syrup to artificial and low-calorie sweeteners such as aspartame, stevia, and allulose. Find out how natural sweeteners compare to sugar and impact blood sugar levels. Learn about the latest research on artificial sweeteners, including recommended consumption limits and safety concerns. This episode will allow you to make an informed decision about what natural and artificial sweeteners are safe and which you may want to avoid or limit during pregnancy and breastfeeding.

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Nutritive Sweeteners

Sweeteners are divided into two categories: nutritive (containing calories) and non-nutritive (without calories). Sugar and most other natural sweeteners fall into the nutritive category because they provide calories and are primarily composed of glucose and fructose in varying ratios. Sucrose (table sugar) is a common example, consisting of 50% glucose and 50% fructose. Other natural nutritive sweeteners, like honey, maple syrup, and molasses, have slightly different compositions and may contain trace amounts of vitamins, minerals, or antioxidants. Despite these differences, all nutritive sweeteners share a similar level of sweetness. They are typically listed on ingredient labels under familiar names, with their sugar content included in the total or added sugars on nutrition labels.

Quantifying Sweetness

Sweetness is determined by how compounds interact with sweet taste receptors on the tongue. Factors like sweetness intensity, how long the sensation lingers, concentration, and temperature affect how sweetness is perceived. Natural sugars tend to have a moderate sweetness that fades quickly, while artificial sweeteners can be much sweeter and linger longer.

Scientists measure sweetness using a combination of methods. Sensory evaluations involve trained testers comparing the sweetness of a substance to sucrose. Instruments like electronic tongues analyze chemical interactions between sweeteners and taste receptors to quantify sweetness. Receptor interaction studies examine how compounds bind to sweet taste receptors.

Glycemic Index

One way to compare nutritive sweeteners is to look at their glycemic index (GI). The glycemic index is a scale from 0 to 100 that measures how quickly a food raises blood glucose levels. Glucose, the body’s primary energy source, is at the top of the scale with a GI of 100. High-GI foods (70 and above) cause a rapid spike in blood sugar. Low-GI foods (55 or below) are digested more slowly, leading to a more gradual rise in blood sugar. Since all nutritive sweeteners contain some combination of glucose and fructose, they affect blood sugar differently. Sweeteners with more glucose tend to have a higher glycemic index. Those with more fructose have a lower glycemic index, as fructose is metabolized differently and does not cause an immediate blood sugar spike. Below is a breakdown of the glycemic indexes of common sugar alternatives.

Glucose	100
Sucrose (sugar: 50% glucose + 50% fructose)	65
Molasses	55
Maple syrup	54
Honey	50
Coconut sugar	35
Maltitol (sugar alcohol)	35
Fructose	25
Agave syrup	15
Xylitol (sugar alcohol)	12
Sorbitol (sugar alcohol)	4
Lactitol (sugar alcohol)	3
Isomalt (sugar alcohol)	2
Mannitol (sugar alcohol)	2
Erythritol (sugar alcohol)	1

All carbohydrate-containing foods have a glycemic index because they break down into sugars that affect blood glucose levels. The GI of a food depends on how quickly it is digested and absorbed. Simple carbohydrates, like sugar and white bread, have a high GI because they are rapidly converted into glucose, causing a quick rise in blood sugar. Complex carbohydrates, like whole grains and legumes, tend to have a lower GI because they take longer to digest, leading to a slower, more gradual increase in blood sugar. Fiber-rich foods and some starches have the lowest GI, as they slow digestion and glucose absorption. Below is a breakdown of the glycemic indexes of common foods.

Pretzels	83
White rice	73
White bread	70
Brown rice	66
Sweet potato	63
Whole wheat bread	60
Pineapple	59
Banana	51
Carrots	39
Apple	38
Greek yogurt	34
Milk (whole)	31
Dark chocolate (70%+ cocoa)	23
Almonds	15
Avocado	15

The glycemic index is one tool for comparing nutritive sweeteners. Let’s examine some of the most common nutritive sweeteners, how they are made, their composition, and their potential nutritional benefits beyond sweetness.

Molasses

Molasses comes from refining sugar from sugar cane or beets. It has a glycemic index of 55 and is about 29% sucrose, 12% glucose, 13% fructose, and 22% water. It also contains trace amounts of B6, calcium, magnesium, iron, and potassium.

Maple Syrup

Maple syrup comes from maple trees. It has a glycemic index of 54 and is 67% sugars, primarily sucrose with small amounts of glucose and fructose, and about 32% water. Many products sold as syrup are not maple syrup but contain high-fructose corn syrup and artificial flavors. Popular brands like Mrs. Butterworth’s, Log Cabin, and Aunt Jemima contain no real maple syrup, so it’s essential to check the label if you’re looking for pure maple syrup. Real maple syrup also contains trace amounts of manganese, zinc, calcium, potassium, iron, and antioxidants.

Honey

Humans have used honey for thousands of years. Bees make honey, and the flavor can vary based on where it is from and the flowers where the bees collect nectar and pollen. Honey has a glycemic index of 50 and is about 32% glucose, 38% fructose, and 17% water. It also contains trace amounts of B vitamins, vitamin C, calcium, iron, zinc, potassium, phosphorous, magnesium, selenium, chromium, and manganese. Honey also contains antioxidants; generally, the darker the honey, the more antioxidants it has.

Coconut Sugar

Coconut sugar is from the sap of the coconut palm tree. Coconut sugar has a glycemic index of 35 and is about 70–79% sucrose and 3-9% of each glucose and fructose.

Agave Syrup or Agave Nectar

Agave syrup is made from the agave plant, which produces tequila. It has a glycemic index of 15 and contains about 20% glucose, 56-60% fructose, and trace amounts of sucrose.

Sugar Alcohols

Sugar alcohols, or polyols, are commercially used as sugar substitutes. Polyols include sorbitol, xylitol, lactitol, mannitol, erythritol, isomalt, and maltitol. They are mainly used to sweeten sugar-free candy, cookies, and chewing gums. Sugar alcohols have a glycemic index ranging from 1-12. They are 25% to 100% as sweet as sugar and have 1/3 to 1/2 fewer calories. A benefit is that they do not promote tooth decay or cause a spike in blood glucose as sugar does. A downside is that the side effects of these can be bloating and diarrhea.

Substituting Other Sweeteners for Sugar

While natural sweeteners may have slightly different effects on blood sugar, their overall carbohydrate and sugar content is not significantly different. From a nutritional standpoint, these sweeteners like honey, maple syrup, and molasses provide trace amounts of beneficial nutrients not found in table sugar. These small amounts of vitamins, minerals, and antioxidants are not significant enough to justify consuming them for their health benefits alone. If you add a sweetener to a cup of tea, you may prefer one lower on the glycemic index or that offers trace nutrients. Ultimately, the best choice comes down to personal taste.

Non-nutritive Sweeteners

Non-nutritive sweeteners have zero calories and include artificial sweeteners and a few plant-based options, such as stevia and monk fruit extract. Non-nutritive sweeteners are attractive because they substitute the sweetness of sugar with zero calories. Identifying these sweeteners on ingredient lists can be more difficult, as they often appear under unfamiliar names. Since they contain no sugar, they are not listed under total or added sugars on nutrition labels. Unlike nutritive sweeteners, all non-nutritive sweeteners have a zero glycemic index, meaning they do not directly impact blood sugar levels.

The Importance of Sweeteners from an Ancestral Perspective

Throughout human evolution, our brains have linked sweetness to calorie-rich foods. This is a survival mechanism to help us seek out energy-dense food sources. Today, we can access sweeteners that provide intense sweetness without nutritional value or calories. Some scientists argue that these artificial sweeteners may disrupt our ability to regulate hunger and food intake.

Animal studies have shown potential effects on appetite and metabolism. One study on rats found that intake of foods or fluids containing non-nutritive sweeteners was accompanied by increased food intake, body weight gain, accumulation of body fat, and weaker caloric compensation compared to consumption of foods and fluids containing glucose. In humans, research investigating a link between diet soda consumption and obesity used MRI scans to observe brain activity while consuming nutritive and non-nutritive sweeteners. The findings suggest alterations in reward processing of sweet taste in individuals who regularly drink diet soda, which is associated with the degree of consumption.

The Use of Non-nutritive Sweeteners During Pregnancy and Breastfeeding

Pregnancy is often when you become more mindful of your diet and make healthier choices. For many expecting moms, this means cutting back on sugar, which often increases sugar substitutes. In one review, about 30% of expecting mothers reported intentionally consuming non-nutritive sweeteners. Since these ingredients are often hidden in processed foods, that total is likely much higher. Another study found that 98% of expecting mothers used non-caloric sweeteners.

A small study analyzed breast milk from 20 mothers and found non-nutritive sweeteners (saccharin, sucralose, and acesulfame-potassium) were present in 65% of the samples. For more evidence-based information on how various substances affect breastfeeding and whether they transfer into breast milk, the LactMed database is a fantastic tool. We will review the LactMed data for each sweetener discussed in this article. There are cautions LactMed notes for every artificial sweetener: Ingestion of diet drinks containing low-calorie sweeteners might increase the risk of vomiting in breastfed infants. They also note some authors suggest that women may wish to limit the consumption of nonnutritive sweeteners while breastfeeding because their effect on nursing infants is unknown.

Acceptable Daily Intake

The FDA has established an acceptable daily intake (ADI) level for sweeteners. An ADI is the amount of a substance considered safe to consume each day over the course of a person’s lifetime. According to the FDA, an additive does not present safety concerns if the estimated daily intake is less than the ADI. The FDA lists safe levels of sweeteners based on the number of sweetener packets a person can consume and still be at the safe level. The FDA does not have separate or additional guidelines for consuming sweeteners during pregnancy.

The FDA assumed a sweetener packet is as sweet as two teaspoons (approximately 8 grams) of sugar for these comparisons. This is about accurate given the amount of sweetener and other additives in a packet serving size. The ADI is also based on a person who weighs 132 pounds (60 kg). According to CDC data, the average weight of an adult man in the United States is 199.8 pounds (90.6 kg), and the average weight of an adult woman is 170.8 pounds (77.5 kg). The number of packets per day is relatively high for all sweeteners, and it is unlikely you would exceed the limit, even if it were adjusted for a more realistic body weight.

Additives to Artificial Sweeteners

Non-nutritive sweeteners often include other additives to improve texture or flavor. Stabilizers and anti-caking agents prevent clumping and improve texture. Silica is used as an anti-caking agent to keep powdered sweeteners from clumping. Cellulose powder helps maintain consistency in powdered sweeteners. Some sweeteners contain preservatives to extend shelf life. Sodium benzoate is a common preservative in liquid non-nutritive sweeteners. Potassium sorbate is used to prevent spoilage in certain sugar substitutes.

Many non-nutritive sweeteners also contain bulking agents to increase the volume of a package, making them easier to measure. Because these sweeteners are significantly sweeter than sugar, only a small amount is needed. However, since we are accustomed to using a standard packet or teaspoon of sugar, bulking agents help maintain a familiar portion size, making it easier to gauge how much to add. Dextrose is a carbohydrate derived from corn, often used in sweetener packets like Stevia in the Raw and Equal. Maltodextrin is a processed starch from corn, rice, or potatoes commonly found in Splenda. Erythritol is sugar alcohol from corn or wheat starch that adds bulk while maintaining a low-calorie count. It is found in Truvia and Monk Fruit in the Raw.

Prebiotic fiber additives can create a sugar-like texture and claim additional health benefits for your gut. Inulin, a plant-based fiber used in SweetLeaf Stevia to provide bulk, is a prebiotic that feeds beneficial gut bacteria.

Lastly, natural and artificial flavors are added to improve taste and mask bitterness or aftertaste from artificial sweeteners. Natural flavors is a broad term for plant or animal-derived flavor compounds. Artificial flavors are synthetic compounds designed to improve sweetness perception. These broad categories allow companies to protect trademarked recipes by not disclosing the exact ingredients used.

Examining Non-nutritive Sweeteners

Non-nutritive sweeteners encompass a diverse range of compounds, each with unique characteristics. They differ in composition, sweetness compared to sugar, the additional ingredients used in their formulations, and the recommended limits for safe consumption. To understand their individual benefits and potential risks, it is important to evaluate each sweetener separately, particularly regarding their safety and effects during pregnancy and breastfeeding.

Stevia

Stevia is from steviol glycosides extracted from the stevia plant leaves. Stevia has been utilized as a sweetener in South America for hundreds of years and in Japan since 1970. It is 200 to 400 times sweeter than sugar. Stevia typically comes in green single-serving size packets. Stevia in the Raw contains dextrose as a bulking agent. One packet has less than one gram of carbohydrates and less than four calories. The FDA considers this zero calories per serving. Truvia contains erythritol as a bulking agent and natural flavors. Sweet Leaf contains inulin, a bulking agent and prebiotic fiber, and silica as an anti-caking agent. The FDA lists steviol glycosides as generally recognized as safe (GRAS). This requires the same safety standards as an FDA-approved food additive. The acceptable daily intake (ADI) is 27 packets.

No data exist on the excretion of any components of stevia into breast milk or on the safety and efficacy of stevia in nursing mothers or infants. According to LactMed, although the risk to the breastfed infant appears to be low, an alternate artificial sweetener with more data available may be preferred, especially while nursing a newborn or preterm infant. More research on stevia is discussed later in this article.

Monk Fruit Extract

Monk fruit extract, also called luo han guo fruit extract, is 100-250 times sweeter than sugar. Monk Fruit in the Raw is a popular brand that comes in orange packets and has erythritol as a bulking agent. The FDA recognizes monk fruit extracts as generally recognized as safe (GRAS), but the FDA sets no acceptable daily intake (ADI) for this sweetener. Monk fruit extract is one of the newer non-nutritive sweeteners available, and we don’t have much data on it. There were no results in the LactMed database.

Aspartame

Aspartame is an artificial, low-calorie sweetener that combines two amino acids, phenylalanine and aspartic acid, along with a small amount of methanol. When you digest aspartame, your body breaks it down into these three components. There is a rare hereditary disease known as or PKU. Someone with this condition cannot metabolize this amino acid and should avoid aspartame.

This sweetener is 200 times sweeter than sugar. Aspartame isn’t heat-stable, so it is not typically in baked goods. This sweetener is used in Diet Coke and is in blue packets of Equal. Although Equal is primarily aspartame, it also includes acesulfame potassium, another sweetener we discuss below. Equal also contains dextrose and maltodextrin as bulking agents. The FDA approves aspartame as a general-purpose sweetener. The acceptable daily intake (ADI) is 75 packets.

According to LactMed, aspartame does not cross through the placenta because it is fully digested in the gastrointestinal tract. When consumed in typical amounts, aspartame does not transfer in breast milk. One study showed that a large intake of aspartame (equivalent to 17 cans of soda or 100 packets of Equal Sweetener) could slightly increase the amount of phenylalanine in breast milk. If your infant has PKU, you should talk to your doctor or pediatrician about consuming aspartame, but typically, it is not an issue. LactMed also notes that an association between low-calorie sweeteners, especially aspartame, and the risk of autism in boys has been found, but more data are needed to establish a cause-and-effect relationship.

Many questions have been raised over the years about the safety of aspartame. One recent animal study foundaspartame consumption at doses equivalent to only 7–15% of the FDA-recommended maximum daily intake value for humans produces significant deficits in spatial learning and memory. Plus, the learning and memory deficits are transmitted by aspartame-consuming male mice to their male and female offspring.

Advantame

Advantame is an analog of aspartame that is 20,000 times sweeter than sugar. This is used commercially and is often blended with other sweeteners to improve taste and reduce bitterness. It is not available for retail purchase or in single-serving packets. The FDA approved advantame in 2014 as a general-purpose sweetener and flavor enhancer. The acceptable daily intake (ADI) is 4,920 packets. Advantame does not appear in the LactMed database.

Neotame

Like advantame, neotame is an analog of aspartame that is 7,000-13,000 times sweeter than sugar. Neotame goes by the brand name Newtame and is made by NutraSweet. This is used commercially and is not available in single-serving packets. The FDA approved neotame in 2002 as a general-purpose sweetener and flavor enhancer. The acceptable daily intake (ADI) is 23 packets.

Neotame does not appear in the LactMed database. There is recent evidence that neotame may have harmful effects on gut health. Research shows neotame can damage intestinal cells and weaken the intestinal barrier. It is also shown to alter gut bacteria in a way that could promote disease. Hopefully, we will have more long-term data on safety in the future.

Sucralose

Sucralose is made by chemically modifying sucrose (table sugar, 50% glucose, and 50% fructose) by replacing three hydroxyl groups with chlorine atoms. This modification prevents the body from metabolizing sucralose for energy, making it virtually calorie-free. Sucralose is 600 times sweeter than sugar. Splenda is the brand name of the sucralose that comes in yellow packets. This also contains dextrose and maltodextrin as bulking agents. The FDA approves sucralose as a general-purpose sweetener. The acceptable daily intake is 23 packets.

According to LactMed, sucralose transfers through breast milk. Sucralose is poorly absorbed after oral ingestion and is not found in the plasma of most breastfed infants after maternal ingestion of sucralose. Some authors note that the levels of sucralose in milk can exceed the sweetness threshold in milk and affect intestinal enzymes and the microbiome.

Data from an animal trial found that sucralose transfers in utero. The researchers conclude that pre- and post-natal exposure to sucralose via maternal ingestion causes marked metabolic and microbiome alterations, which could give rise to future metabolic disease.

Acesulfame Potassium

Acesulfame potassium (also called acesulfame K or ace-K) is an artificial sweetener often used with other sweeteners to enhance sweetness and mask any aftertaste. It is commonly used in frozen desserts, candies, beverages, and baked goods. Acesulfame potassium is 200 times sweeter than sugar. This is commercially available fromSunnet and SweetOne. You cannot buy it in packets as a standalone sweetener, but it is combined with aspartame in Equal. The FDA approves acesulfame potassium as a general-purpose sweetener, and the acceptable daily intake (ADI) is 23 packets.

According to LactMed, acesulfame transfers into breast milk. They note that even some mothers who reported not consuming artificial sweeteners have small amounts of acesulfame in their breast milk. This finding shows that these ingredients are prevalent in our diets. You are likely consuming artificial sweeteners and don’t even know it. Although it is present in breast milk, LactMed states it is not likely to reach an intake greater than the acceptable daily intake for infants.

Data from an animal trial found that acesulfame potassium also transfers in utero. The researchers conclude that pre- and post-natal exposure to acesulfame potassium via maternal ingestion causes marked metabolic and microbiome alterations, possibly leading to future metabolic disease. More research shows that exposure to acesulfame potassium in utero and through breast milk can influence taste preferences in mice. They found that mice exposed to acesulfame potassium in utero and via breast milk had a greater preference for sweet foods after birth.

Saccharin

Saccharin, discovered in 1879, is the first artificial sweetener. It is 200-700 times sweeter than sugar. A popular brand is Sweet & Low, which comes in pink packets and also contains dextrose as a bulking agent and potassium bitartrate (cream of tartar) as a stabilizing and anti-caking agent. The FDA approves saccharin as a general-purpose sweetener, and the acceptable daily intake (ADI) is 45 packets.

According to LactMed, because of the low levels of saccharin in breastmilk, amounts ingested by the infant after typical maternal intake are small and would not be expected to cause any adverse effects in breastfed infants and not likely to reach an intake greater than the acceptable daily intake. An animal study found saccharin in amniotic fluid and fetal bladder, so we know it crosses the placenta.

Allulose

Allulose is the newest addition to this list and is classified as a rare sugar that occurs naturally in small amounts in figs, raisins, jackfruit, and maple syrup. It is considered a non-nutritive sweetener because it has 0.2–0.4 calories per gram, compared to traditional sugars like sucrose, which has four calories per gram. Most commercially available allulose is made through enzymatic conversion from corn or other plant starches. It is chemically similar to fructose, but your body processes it differently. It is absorbed in the small intestine but not metabolized for energy, so it is excreted in urine. The result is minimal calories and no significant impact on blood sugar.

Allulose has a similar taste and texture to sugar but is only about 70% as sweet. It is a versatile alternative for cooking and baking. Allulose has been available commercially since 2015. Unlike many other sweeteners, it does not come in single-serving packets but is available in larger quantities in retail stores from many brands. The FDA approves allulose as Generally Recognized as Safe (GRAS). In the United States, it is exempt from being listed as part of total or added sugars on nutrition labels.

Allulose is not in the LactMed database. The initial research on allulose looks promising; hopefully, we will see more long-term data.

Artificial Sweeteners and Cancer

Concerns about artificial sweeteners and cancer initially arose when early studies linked the combination of cyclamate plus saccharin with the development of bladder cancer in rats. As a result, cyclamate was banned in the United States in 1969. Although since then, scientists have concluded that cyclamate does not cause cancer, it has not been reapproved in the U.S., although it is approved in many other countries.

In the 1970s, studies showed that very high doses of saccharin caused bladder cancer in rats. As a result, saccharin was labeled as a possible carcinogen. Since then, further studies have found that the mechanism causing bladder cancer in rats was specific to rodents and does not apply to humans. Large-scale human studies found no clear link between saccharin consumption and cancer. Saccharin is not considered carcinogenic and is deemed safe when consumed within the acceptable daily intake (ADI).

In 2023, the International Agency for Research on Cancer and other agencies classified aspartame as a possible carcinogen. They cite limited evidence and reaffirmed the acceptable daily intake of 40 mg/kg body weight. This is the equivalent of 9-14 cans of soda for an adult weighing 155 pounds (70kg). In response, the FDA disagrees with IARC’s conclusion and states aspartame being labeled by IARC as “possibly carcinogenic to humans” does not mean that aspartame is actually linked to cancer. The FDA states that aspartame is one of the most studied food additives in the human food supply, and FDA scientists do not have safety concerns when aspartame is used under approved conditions.

There is no clear evidence that artificial sweeteners are carcinogenic in humans.

Research on Artificial Sweeteners During Pregnancy

We deeply understand how sugar affects our health and how it is processed. However, we still know little about the effects of artificial sweeteners and even less about their effects during pregnancy.

One study found that aspartame consumption was associated with an increased risk for infertility, and the time to conceive was longer in the group who consumed a higher amount of aspartame. To investigate further, they followed up with an animal study that showed increased oxidative stress and mitochondrial dysfunction in the reproductive system. There is also evidence that acesulfame potassium may impact fertility.

We know most artificial sweeteners cross the placenta and transfer into breast milk. A systematic review and meta-analysis found artificial sweetener consumption during pregnancy is associated with an increased risk of preterm delivery (by 18%). However, researchers note that the evidence is low-certainty. Some research has linked increased rates of childhood obesity, although there are many variables, and we really need more research. There is quite a bit of evidence that artificial sweeteners can alter the gut microbiome. You can read more in this comprehensive review of the literature on both animals and humans. Hopefully, we will see more data in the future, especially in pregnant women.

Should You Avoid Artificial Sweeteners During Pregnancy?

When considering artificial sweeteners during pregnancy, it’s essential to recognize that while they may seem like a simple substitute for sugar, they are not metabolically neutral. Research suggests they are generally safe within recommended limits, but concerns remain about their potential impact on the gut microbiome and long-term influence on taste preferences. Most studies are based on animal models, and more research is needed to fully understand their effects on human health over time.

A diet rich in whole, unprocessed foods is always the best foundation for nutrition, with water as the primary drink of choice. To reduce sugar intake, consider using natural sweeteners like honey or agave, which have a lower glycemic index. Your approach should align with your health goals—whether it’s managing blood sugar, cutting calories, or simply making mindful dietary choices. The occasional use of artificial sweeteners differs from frequent consumption, and awareness of how often you use them can help you make an informed decision. Ultimately, whether you choose to avoid, limit, or continue consuming artificial sweeteners is a personal choice. If you have concerns or questions, please bring them up with your doctor or midwife.

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