Lecithin is one of the most common phosphorus based additives – even though it doesn’t have phosphorus in it’s name (more about that in my previous post). There are many phosphorus-based additives that fall into this category and the research community is starting to highlight them as additives of concern.
But is lecithin associated higher phosphorus in foods? Because, if it isn’t then patient’s trying to manage hyperphosphatemia can probably eat it.
So let’s dig in. Today’s key reference is:
List, G. R. “Soybean lecithin: Food, industrial uses, and other applications.” Polar lipids (2015): 1-33.
What is lecithin?
Lecithin is a phosphatide. Phosphatides are a type of phospholipids derived from glycerol phosphates. The production of lecithin started in the 1920s as a by-product of the oilseed industry. By the 1940s the use of lecithin was well established in the food industry.
Producers derive lecithin from soybeans, however, they can also source it from canola or sunflower oil. According to the National Library of Medicine Pub Chem website, the molecular structure of lecithin is C42H80NO8P. Lecithin has a molecular weight of 758.1g/mol. With only 1 molecule of phosphorus, this means that lecithin is approximately 4% by weight phosphorus.
What purpose does lecithin have in food?
Lecithin is used as an:
- emulsifier
- wetting agent
- viscosity reduction
- release agents
- crystallization control
What food products might contain lecithin?
Lecithin may be found in:
- margarine
- shortenings
- baked foods/doughs
- chocolates
- candies
- noodles/pasta
- ice cream
- instant cocoa beverages
- powdered milks
- other food powders that might crystalize (such as juice powders)
However, according to the National Medicine Pub Chem website, there are 440 foods associated with lecithin as a food additive or an ingredient.
Why add lecithin to baked foods and doughs?
Doughs with lecithin are more stable, elastic and drier, which makes them easier to handle. And, the end products are considered higher quality. Lecithin is also helpful when added to reduced-fat baked goods, as it helps prevent the dough from sticking to equipment. In bread products specifically, lecithin increases the loaf volume and increases shelf life.
Why is lecithin added to powdered or instant foods and beverages?
Depending on the type of food being powder, lecithin can have different roles. In high fat foods, which are more likely to repel water, lecithin’s hydrophilic properties can make these foods easier to blend. In high protein foods, lecithin can slow down the absorption of water making it less likely to clump.
Why is lecithin added to candies and chocolates?
One of the most established and routinely used foods for lecithin are candies and chocolates. Lecithin helps reduce bloom formation on chocolates, prevents candies from sticking to wrappers and improves the softness of chewing gum. When lecithin is used in chocolate is reduces the amount of cocoa butter required by altering the viscosity.
What are the other uses for lecithin in food?
In addition to the above uses, lecithin has a long list of miscellaneous uses including:
- extending egg yolks
- meat curing
- frying
- reduced-fat margarine production
- aerosol non-stick pan spray
- emulsifier in creamy products
- nutrient in mushroom product
How much lecithin is added to foods?
Based on the article, food manufacturers need to add varying amounts of lecithin to achieve ideal end-products, depending on the food type. In the table below, I provide the food type and amount of lecithin needed based on the categories and numbers in our key reference.
To provide some context, in the last two columns I have worked out what that would mean for total amount of lecithin and phosphorus in milligrams per 100g of food. When I mention “in the flour”, by this I mean that there could be lecithin in the other ingredients not factored into this equation.
| Food Type | Amount of Lecithin | Amount lecithin per 100g food | Amount phosphorus per 100g food |
| Dough | 0.2-0.5% | 20-50mg | 0.8mg-2mg |
| Bread | 0.2-0.7% by flour weight | 20-70mg in the flour | 0.8-2.8mg in the flour |
| Cookies and Crackers | 0.2-0.5% by flour weight | 20-50mg in the flour | 0.8-2mg in the flour |
| Cakes and Donuts | 1-3% | 1000-3000mg | 40-120mg |
| Icing and Fillings | 0.2-1% | 20-1000mg | 0.8-40mg |
| Pizza, Pie Crusts, Tortillas and Flat Breads | 0.2-0.5% by flour weight | 20-50mg in the flour | 0.8-2mg in the flour |
| Instant products | 0.2-10% | 20-10,000mg | 0.8-400mg |
| Chocolates, candy coatings, caramels/fudge, toffees and brittles | 0.2-0.6% | 20-60mg | 0.8-2.4mg |
| Chewing gum and cocoa powders | 0.5-5% | 50-5000mg | 2-200mg |
| Protein drinks | 2% | 2000mg | 80mg |
Is the amount of phosphorus clinically relevant?
I think the answer here is that it depends. In some products, for example an instant product that ends up adding 400mg of phosphorus to the diet could be clinically relevant. However the addition of 0.8mg to the diet isn’t clinically relevant.
The two factors that would need to be considered are:
- How much of the product is your patient actually eating.
- How much lecithin has been added to the product.
Let’s take a look at a few potential scenarios:
Scenario 1: Your patient drinks a 250mL protein drink every day for breakfast that contains 2% lecithin. The total weight on the protein drink is 250g. This would mean they are consuming 5000mg of lecithin with each breakfast, which equates to 200mg of phosphorus. That’s a big phosphorus load.
Scenario 2: Your patient eats 4 slices of bread everyday (2 slices of toast at breakfast and a sandwich at lunch). Their bread contains somewhere between 20-70mg of lecithin per 100g of flour. According to a quick google search, the average loaf of bread is about 1 pound (454g) and is about 50% water, meaning that it contains about 250g of flour (I am rounding to make the math easier, as obviously it will depend on the recipe). There are 20-24 slices of bread in the average loaf.
So for the total loaf of bread (250g flour) there is 50-175mg of lecithin and 2-7g of phosphorus. This works out to a max of 0.35g of phosphorus per slice of bread. Even if your patient consumes 4 slices of bread, their total phosphorus load from the lecithin in the flour only works out to a max of 1.4g.
The wrench in these calculations: This calculation only factors in lecithin added to the flour. It doesn’t necessarily consider any lecithin that might be in other ingredients.
How does this compare with other studies looking at lecithin from phosphorus content?
There really hasn’t been many studies that have examined this, though I did look at this in my PhD. Unfortunately, the lecithin results by product type didn’t make it in the final published version of the manuscript, but here is what I said about it in one of the earlier drafts:
Protein bars which contained lecithin had more phosphorus per serving compared to bars without any phosphorus additives (Table 3). This difference failed to reach statistical significance when considered by 100g but approached statistical significant for considered per serving.
Among the processed grain products, lecithin as a sole phosphorus additive was found frequently in cold cereal products, cookies and crackers (194 (23.1%), 128 (58.9%) and 137 (44.1%) respectively). In these products, those containing lecithin had lower amounts of phosphorus than products without lecithin, though this difference did not achieve statistical significance in the case of cookies (Table 3).
Table 3: Difference in phosphorus content in food products with and without lecithin
| Product | Phos per serving with Lecithin | Phos per serving without Lecithin | Difference | p-value |
| Protein Bars | 141 ± 181 | 96 ± 46 | +45 | 0.05 |
| Cereal | 65 ± 48 | 114 ± 81 | -49 | <0.01 |
| Cookies | 63 ± 78 | 18 ± 12 | -46 | 0.88 |
| Crackers | 25 ± 15 | 55 ± 38 | -30 | <0.01 |
p-value calculated using ANOVA with Games-Howell post-hoc testing. <0.05 considered statistically significant.
Take Aways
Lecithin is a common phosphorus additive, found in many types of food. However, whether or not it is an additive of concern for hyperphosphatemia management likely depends on the types of foods it is being use in.
