Dulse, a type of red seaweed, is rising in popularity today for both its culinary and medicinal purposes.
In this article, we will look at the health benefits of dulse, its safety, and its history.
Table of Contents
What is Dulse?
Dulse, known scientifically as Palmaria palmata, is a type of red seaweed found on the northern coasts of the Atlantic and Pacific Oceans. It primarily grows in cold waters on rocky coasts, and can even be located as far north as the Arctic Circle.
Dulse is one of the more aesthetically pleasing seaweeds, with a deep crimson color.
Like other seaweeds, dulse is rich in numerous nutrients, including vitamins, minerals, and phytochemicals.
Specifically, dulse is known for its relatively high protein and amino acid content, as well as:
- Vitamin K
- Several B-vitamins (e.g. B1, B2, B3)
- Calcium
- Magnesium
- Potassium
- Iodine
- Polysaccharides
- Kainic acid
- Beta-carotene
Moreover, dulse, like all red seaweeds, is particularly high in flavonoids, phenolic acids, and other antioxidant compounds.
Last but not least, dulse contains a high amount of eicosapentaenoic acid (EPA), a type of omega-3 fatty acid; it also has a favorable omega-3 to omega-6 ratio (usually around 1:1).
Health Benefits of Dulse:
With its diverse and dense nutrient profile, it may come as little surprise that dulse benefits the body in a number of different ways. While research is still growing and likely to elucidate more health benefits down the road, dulse thus far appears to offer the following effects on human health:
1. Antioxidant Properties
It is likely that dulse benefits the body due to its high concentration of antioxidants, which are important for warding off many chronic diseases and improving overall health.
One of the earlier studies on dulse found that a polyphenol-rich dulse extract was able to offer significant free-radical scavenging activity, while also inhibiting lipid peroxidation. Dulse extract was also found to have antiproliferative effects.
Another study investigated dulse extract and found that eicosapentaenoic acid (EPA) was the most abundant fatty acid in dulse. EPA has significant antioxidant and free radical-inhibiting activity.
Another study found that a protein hydrolysate extract from Palmaria palmata contained 15 different antioxidant peptides.
These results are similar to another study on dulse extract, which found similar antioxidant properties. They concluded it could be useful in nutraceuticals and functional foods.
Summary:
Dulse appears to have antioxidant activities, although direct human studies are needed to confirm this finding.
2. Anti-Inflammatory Properties
Antioxidant and anti-inflammatory effects go hand in hand, so it’s no surprise that dulse may also reduce inflammation.
In a human cell study, a phenolic extract from dulse was able to decrease markers of inflammation, such as neutrophils, cytokines, and pro-oxidants. The researchers concluded that these decreases in inflammatory markers could make dulse a candidate for preventing some health disorders, including atherosclerosis.
Another study found that a water extract of dulse was able to decrease inflammatory markers in murine cells while helping to decrease overall inflammation. In this study, phycobiliproteins and chlorophyll seemed to be the compounds most responsible for these anti-inflammatory effects.
Surprisingly, a randomized parallel placebo-controlled clinical trial found that administering dulse-enriched bread actually increased C-reactive protein and other inflammatory markers. The authors noted that the changes were within clinical ranges and that the increase in some inflammation could provide potential immunostimulatory effects.
Based on this study alone, and the general lack of human research, more studies are needed.
Summary:
Several studies show that dulse may be helpful in inflammation reduction, however, based on the general lack of human research, more studies are needed.
3. Anti-Diabetic Properties
There also appear to be a few ways dulse benefits diabetes and overall metabolic health.
First, a randomized, double-blind placebo-controlled trial found that taking dulse capsules (2g/day) for 8 weeks led to decreased triglycerides in women, although there weren’t any significant improvements in glycemic control or other metabolic markers compared to controls.
Another study looked into both the in vitro and in vivo effects of different peptides from Palmaria palmata protein hydrolysate peptides.
In the in vitro portion, they found that dulse peptides inhibited the DPP-IV enzyme, while also increasing overall hormonal activity related to glucose control. Inhibiting DPP-IV essentially increases insulin sensitivity and the overall duration of insulin, which aids diabetes.
In the in vivo portion, it was found that these same peptides led to significant increases in insulin and significant decreases in blood glucose compared to controls.
In another animal study, dulse extract was shown to significantly reduce blood glucose and increase insulin, while also improving beta cell function. Moreover, it led to greater glucose tolerance and lower cholesterol and triglycerides compared to controls.
These results are similar to an in vitro study which showed that protein hydrolysate from dulse was able to offer insulinotropic activity, including an increase in insulin, DPP-IV inhibition, and incretin hormones. And the in vivo portion of this study showed that dulse led to improved glucose tolerance.
Summary:
Research shows that dulse may be beneficial for diabetes and metabolic health.
4. May Lower Blood Pressure
Lastly, dulse may benefit blood pressure and overall heart health.
In a study with hypertensive rats, researchers found that both the protein hydrolysate and specific tridecapeptide from dulse led to significant reductions in blood pressure. In fact, the drop was over 30mmHg in both cases.
Also, one in vitro study found that certain peptides from dulse extract were able to effectively inhibit renin enzyme activity. Renin inhibition ultimately leads to relaxed and widened blood vessels, thus lowering blood pressure.
Another in vitro study found that protein hydrolysate from dulse effectively inhibited angiotensin-converting enzyme activity, indicating its role in the prevention or control of hypertension.
Summary:
Dulse may work to lower blood pressure and support heart health but additional human studies are required to verify these findings, although the initial research looks promising.
Dulse Safety:
In general, dulse is safe to take when it is consumed in recommended amounts. The safe range is capped at 4-5g of dried dulse per day.
Individuals with hyperthyroidism should be cautious due to the high iodine content in dulse. As always, it is best to talk with your doctor before implementing a new supplement.
Possible side effects of consuming dulse include nausea, weakness, kidney and thyroid problems, and various digestive symptoms.
Dosing:
Consuming normal amounts of dulse found in food is likely safe. It is most commonly eaten dried, and in this form, one should not exceed 5g per day in most cases.
How to Incorporate into the Diet:
Dulse is very versatile and can be added to the diet in numerous ways. Dulse can be eaten raw or cooked as a snack. It can also be eaten on sandwiches, mixed into baked bread, and even fried up like bacon (some say it even tastes similar to bacon).
Dry dulse flakes can be sprinkled on a number of foods or mixed into salad dressings. Dulse powder can be mixed into smoothies or shakes.
Naming & Taxonomy:
The scientific (latin) name for dulse is Palmaria palmata. It belongs to the Parmeliaceae family within the larger Rhodophyta (red algae) phylum.
It is relatively easy to identify as it typically looks somewhat like red leaf lettuce in its natural, raw form.
Dulse is a flat, red, translucent seaweed with many fronds (leaves) on either side.
History & Traditional Use:
Dulse has medicinal and culinary uses dating back thousands of years. Most of the historical use has been found in Ireland, France, Scotland, Iceland, Norway, and other North-Atlantic countries.
The earliest written records date back to the early 5th century in Ireland and France when dulse was used as a condiment and side dish.
Other records indicate culinary use in Iceland as far back as at least the 10th century, with Norwegian Vikings consuming it on sea expeditions.
Aside from culinary use, dulse also has numerous medicinal uses in its past. For example, Icelanders used dulse in a poultice to fight infection. Dulse was also used to counter sea sickness and hangovers.
Lastly, it was used in Ireland, Wales, and other countries as an insecticide and antihelminthic.
Conclusion:
Dulse has a number of key vitamins, minerals, and phytonutrients important for human health.
Current research suggests that the benefits of dulse include antioxidant and anti-inflammatory effects, diabetes management, and blood pressure reduction. However, more human studies are needed to verify these claims.
Nonetheless, with its solid background of benefits, along with its versatility and pleasing flavor compared to other seaweeds, dulse can easily be incorporated into the diet for potential health benefits.
