Pregnancy tends to be a time when you examine your diet and make healthy changes. For many expecting mothers, this means cutting back on sugar, which often means increasing the use of sugar substitutes. Throughout evolution, humans have learned to tie sweetness to calorie-rich foods. Now we have access to alternatives that taste very sweet but have zero nutritional value and no calories. Plus, in recent years concerns have been raised over the safety of artificial sweeteners, especially during pregnancy. This article examines the evidence on natural and artificial sweeteners and their safety during pregnancy and breastfeeding.
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Nutritive (Contain Calories) Sweeteners
Sweeteners are broken down into two categories, nutritive (contain calories) and non-nutritive (without calories). Sugar and most other natural sweeteners are nutritive in that contain calories and are primarily some combination of glucose and fructose. These have common names you can quickly identify on an ingredient list (like honey or maple syrup), and the nutrient label includes the sugar content within the total or added sugars.
Sweeteners that Contain Sugar
Sugar is 50% glucose and 50% fructose. Some other natural nutritive sweeteners are similar to sugar, but have a different composition of glucose and fructose, and can contain some other trace vitamins, nutrients, or antioxidants. All of these have a sweetness similar to sugar.
One way to compare nutritive sweeteners or sugar substitutes is to look at the glycemic index. The glycemic index is a scale from 1-100 that rates foods based on the rise in your blood glucose level when you consume it. Glucose is at the top of the scale with a glycemic index of 100. All carbohydrates break down into glucose during digestion. White bread has a glycemic index of 70. Below are the glycemic indexes of some sugar alternatives.
|Sucrose (sugar: 50% glucose + 50% fructose)||65|
|Maltitol (sugar alcohol)||35|
|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 of these sweeteners contain some combination of glucose and fructose. Some spike your blood sugar more quickly than others, based on how high the glycemic index is.
Molasses comes from refining sugar from sugar cane or beets. It is about 29% sucrose, 12% glucose, 13% fructose, and 22% water. It also contains some B6, calcium, magnesium, iron, and potassium.
Maple syrup comes from maple trees. It is about 32% water, 67% sugars, primarily sucrose with small amounts of glucose and fructose. If you are buying maple syrup, check the label to make sure you are not getting syrup, which can contain high fructose corn syrup or other sweeteners. Real maple syrup also contains trace amounts of manganese and zinc, calcium, potassium, iron, and antioxidants. Brands like Log Cabin, Mrs. Butterworths, and Aunt Jemima have zero maple syrup and are all corn syrup based.
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 collecting nectar and pollen. Honey is about 32% glucose and 38% fructose and 17% water. It also contains B vitamins, vitamin C, calcium, iron, zinc, potassium, phosphorous, magnesium, selenium, chromium, and manganese. Honey also has some antioxidants. Generally, the darker the honey, the more antioxidants it has.
Coconut sugar comes from the coconut palm. It is about 70–79% sucrose, and 3-9% of each glucose & fructose.
Agave syrup is from agave, the same plant that produces tequila. It is sometimes called agave nectar and is about 20% glucose, 56-60% fructose, and has trace amounts of sucrose.
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. 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 the way sugar does. A downside is that the side effects of these can be bloating and diarrhea.
Substituting Other Sweeteners for Sugar
All of these natural sweeteners are very similar to sugar in that they are primarily some combination of glucose and fructose. Some sweeteners like honey, maple syrup, and molasses do contain trace vitamins, minerals, and antioxidants that are not in sugar. From a carbohydrate or sugar perspective, they are not significantly different. From a purely nutritional standpoint, you are getting more trace vitamins and minerals from some of these than you would from sugar. It is not in high enough amounts to justify consuming large quantities of any of these natural sweeteners for the vitamins, minerals, or antioxidants alone. Those benefits don’t outweigh the downsides of consuming the sugars.
If you have a cup of tea and add a sweetener, you may want to choose a natural sweetener that contains some nutrients other than glucose and fructose. In the broad scheme of things, it likely comes down to your taste preference.
Non-nutritive (without calories) Sweeteners
Non-nutritive sweeteners are all of the artificial sweeteners and a few derived from plants, like stevia and monk fruit extract that do not contain any calories. From a purely caloric standpoint, these may be preferred over sugar because they do not add to your total calorie count. These sweeteners can be more challenging to identify on an ingredient list because some of these go by names that you may not recognize and because they do not contain sugar, they are not included in the total or added sugars on the nutrition facts label. All non-nutritive sweeteners have a glycemic index of zero. All of the sweeteners discussed below FDA approved.
The Importance of Sweeteners from an Ancestral Perspective
Throughout human evolution, we have learned to tie sweetness to calorie-rich foods. Now we have access to alternatives that taste very sweet but have zero nutritional value and no calories. Some scientists argue that artificial sweeteners harm our ability to regulate how much we eat. In animal studies, they found that rats fed artificial sweeteners ate more, gained more weight, and had more fat.
In looking at high rates of obesity among diet soda drinkers, a study took MRI scans to observe brain activity during the consumption of nutritive and non-nutritive sweeteners. They found alterations in reward processing of sweet taste in individuals who regularly consume diet soda. We still have a lot to learn about the long term effects of consuming artificial sweeteners. Still, there is some evidence that changes are going on internally besides just cutting down on calories in your diet. It may be a long time before we know precisely how these non-nutritive sweeteners affect our brains, caloric intake, and food preferences.
The Use of Non-nutritive Sweeteners During Pregnancy
Research often excludes pregnant women, and we are stuck trying to apply data from studies to pregnancy and lactation. There are a lot of animal studies on sweeteners and a fair amount of evidence linked throughout this article. Pregnancy tends to be a time when you examine your diet and make healthy changes. For many women, this means cutting back on sugar, which often means increasing the use of sugar substitutes. A study in Chile found that 98% of expecting mothers used non-caloric sweeteners. Based on a review of nine different studies, researchers found about 30% of expecting mothers reported consuming non-nutritive sweeteners. Given that these ingredients are often hidden in processed foods, that total is likely much higher.
The Use of Non-nutritive Sweeteners During Breastfeeding
One small study analyzed the breastmilk from 20 mothers and found saccharin, sucralose, and acesulfame-potassium present in 65% of the samples. The LactMed database is an excellent resource for how many drugs and chemicals affect breastfeeding and whether they transfer in breastmilk.
Additives to Artificial Sweeteners
You often find additives in non-nutritive sweeteners. Some additives improve texture or flavor. Other additives are bulking agents to increase the quantity in a package, so it is easier to measure. Since many non-nutritive sweeteners are much sweeter than sugar, you need less of them. We are conditioned to be used to the amount of sugar in one packet or one teaspoon. These bulking agents make it easier to know how much you are adding to something like a cup of tea or coffee. Below are some common additives in non-nutritive sweeteners.
- Dextrose or maltodextrin are carbohydrates from corn.
- Erythritol is zero-calorie sugar alcohol from corn or wheat starch.
- Natural flavors can mean just about anything extracted from a plant or animal and added for flavor. Broadly listing natural flavors protects trademarked recipes by allowing companies not to list out the exact ingredients they use in a product. This explanation is a simplified version of a more detailed definition of natural flavors from the FDA.
- Inulin is a prebiotic fiber. Prebiotics feed beneficial bacteria in your gut.
- Silica is an anticaking agent to prevent the powder from clumping together.
Acceptable Daily Intake
The FDA has established an acceptable daily intake (ADI) level for high-intensity sweeteners. The ADI is the amount considered safe to consume each day for 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. They also have calculations for the number of tabletop sweetener Packets a 132 pound (60 kg) person would need to consume to reach the ADI. These all assume one packet is about the equivalent of two teaspoons of sugar, which is about accurate given the amount of sweetener and other additives in a packet serving size. There are no additional guidelines for consumption during pregnancy.
Stevia is from steviol glycosides extracted from the leaves of the stevia plant and is 200 to 400 times sweeter than sugar. The acceptable daily intake is nine packets. You see stevia in little green packets, and a popular brand is Stevia in the Raw. This brand contains dextrose, and one packet has less than one gram of carbohydrates and less than four calories. The FDA considers this zero calories per serving. Other brands are Truvia, which contains erythritol and natural flavors, and Sweet Leaf, which also has inulin and silica.
South America has used stevia as a sweetener for hundreds of years, and in Japan since 1970. The FDA lists steviol glycosides as generally recognized as safe (GRAS) which means that it does not need FDA approval as a food additive. Stevia leaf and crude stevia extracts are not considered GRAS and do not have FDA approval for use in food.
We do not know if steviol glycosides cross the placenta, and there is no data on whether these transfer through breast milk.
Monk Fruit Extract
Monk fruit extract also called luo han guo fruit extract, is 100-250 times sweeter than sugar. The FDA recognizes monk fruit extracts as generally recognized as safe (GRAS), but there is no acceptable daily intake set by the FDA for this sweetener. Monk Fruit in the Raw is a popular brand that comes in orange packets and has erythritol as an added ingredient. Monk fruit extract is the newest of the non-nutritive sweeteners available, and we don’t have a lot of data on it. There were no results in the LactMed database for monk fruit.
Aspartame is approved by the FDA as a general-purpose sweetener and is 200 times sweeter than sugar. It isn’t heat-stable, so it is not typically in baked goods. This is the sweetener in Diet Coke. Aspartame is found in blue packets of Equal which is primarily aspartame, but also includes dextrose with maltodextrin and acesulfame potassium-another sweetener we talk about below. The acceptable daily intake is 75 packets.
When you digest aspartame, your body breaks it down into three components. One of which is the amino acid phenylalanine. There is a rare hereditary disease known as phenylketonuria or PKU. Someone who has this condition cannot metabolize this amino acid and should avoid aspartame.
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. There was one study that showed 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 breastmilk. If your infant has PKU, you should talk to your doctor or pediatrician about consuming aspartame, but typically it is not an issue.
Sucralose is approved by the FDA as a general-purpose sweetener and is 600 times sweeter than sugar. Splenda is the brand name of the sucralose that comes in yellow packets and also contains dextrose and maltodextrin. The acceptable daily intake is 23 packets. Sucralose can be in baked goods, beverages, chewing gum, gelatins, and frozen dairy desserts.
Data from an animal trial found that sucralose transfers to babies in utero and they found effects on the microbiome. According to LactMed, sucralose transfers through breast milk. Some authors note that the levels of sucralose in milk can exceed the sweetness threshold in milk and affect intestinal enzymes and the microbiome.
Acesulfame Potassium (Ace-K)
Acesulfame potassium is included in the ingredient list on the food label as acesulfame K, acesulfame potassium, or Ace-K. This sweetener is 200 times sweeter than sugar. The common brands of this are Sunnet and SweetOne, and this is also an ingredient in Equal. The acceptable daily intake is 23 packets. This sweetener is commonly in frozen desserts, candies, beverages, and baked goods.
According to LactMed, Ace-K does transfer in breastmilk. They note that even some mothers who reported not consuming artificial sweeteners have small amounts of acesulfame in their breastmilk. This finding goes to show that these ingredients are so prevalent in our diets. You are likely consuming artificial sweeteners and don’t even know it.
There is also evidence that Ace-K transfers to babies in utero. More research shows that exposure to Ace-K in utero and through breastmilk can influence taste preferences in mice. They found that mice exposed to Ace-K in utero and via breastmilk had more of a preference for sweet foods after birth.
Saccharin was the first artificial sweetener discovered in 1879. It is 200-700 times sweeter than sugar. A popular brand of this is Sweet & Low, which comes in pink packets and also contains dextrose and cream of tartar. The acceptable daily intake is 45 packets.
An animal study found saccharin in amniotic fluid and fetal bladder, so we know it crosses the placenta.
According to LactMed, amounts ingested by the infant after typical maternal intake is small and would not be expected to cause any adverse effects in breastfed infants. However, some authors suggest that women may wish to limit the consumption of non-nutritive sweeteners while breastfeeding because their impact on nursing infants is unknown.
Advantame and Neotame
Two analogs of aspartame are used commercially and approved by the FDA as general-purpose sweeteners and flavor enhancers. Advantame is 20,000 times sweeter than sugar. Neotame goes by the brand name Newtame and is made by NutraSweet. It is 7,000-13,000 as sweet as table sugar. The acceptable daily intake for advantame is 4,920 packets and 23 packets of neotame. Neither of these sweeteners is in the LactMed database.
Should You Avoid Artificial Sweeteners During Pregnancy?
We have a lot of research, and overall we do not see detrimental effects from non-nutritive sweeteners. There are some red flags showing concerns about gut microbiome health and the impact of non-nutritive or artificial sweeteners on future preferences for sweet foods. Most of the studies have been in animals, and in the future, we should see more evidence on the long term use of these additives in humans.
You know your diet should primarily be healthy whole foods. Your drink of choice should be water. The fewer processed foods you eat and the sweetened beverages you drink, the better. If you are avoiding processed foods and drinks, by default, you will mostly avoid non-nutritive and artificial sweeteners. In a perfect world, we are not eating artificial foods. In reality, we have to find a balance and enjoy what we eat and drink. After reading this, you have a lot more knowledge about sweeteners and sugar substitutes to make informed decisions about what you are eating. Whether you choose to avoid them, cut down on your consumption, or continue eating whatever you want is your choice.
Talk to Your Doctor or Midwife
If you have any questions about sugar substitutes or artificial sweeteners and your consumption of them during pregnancy, please bring up your questions with your doctor or midwife.
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