This study found that consuming 5g of seaweed per day for 4 weeks significantly improved vitamin B12 status in vegetarians.
Vitamin B12 is an essential nutrient found in eggs and dairy products, cheese and yogurt, fermented tofu, kimchi, mushrooms, and other plant foods. Many plant-based milks are also fortified with B12.
A vegetarian diet may be deficient in this vitamin. In a recent report, european nutrition journal investigated how dietary seaweed (from purple seaweed) can improve B12 status in vegetarians.
Vegetarian diet and B12 deficiency
A vegan diet produces only 25% of the greenhouse gas (GHG) emissions of a meat-based diet. However, you should adjust your plant-based diet to ensure you get adequate intake of all the necessary nutrients, including vitamin B12. A recent Taiwanese study found that 26% of vegetarians had vitamin B12 deficiency, compared to 1% of omnivores.
Sea vegetables and B12
Edible plants from the sea, including algae, form part of the diet of East Asia. These contain B12, but also inactive analogs that competitively inhibit B12 absorption.
Purple seaweed is a seaweed (family). new hyperopia). Provides the Recommended Dietary Allowance (RDA) of 2.4 μg. However, Western nutritionists do not support sea vegetables, including nori, as a source of vitamin B12.
Roasted seaweed is often used in Taiwan. The bioavailability of vitamin B12 has not been measured in a well-designed randomized controlled trial (RCT), which led to the current study.
The aim was to test whether seaweed is a bioavailable source of vitamin B12 and whether its intake can adequately improve B12 levels in vegetarians up to the RDA.
About research
The researchers set up an open-label RCT. Participants were between 20 and 60 years old, had been vegetarian for at least one year, and had not taken supplements containing B12, folic acid, or fortified yeast. Other confounders were also excluded.
Those already consuming eggs, dairy products, and fortified plant milks were specifically instructed to continue with the same dietary pattern, as their B12 measurements would be adjusted according to their baseline.
Participants were placed in one of three groups: a control group (no seaweed), a low-dose group (5g of seaweed or 2.4μg of vitamin B12 per day), and a high-dose group (8g of seaweed or 4μg of vitamin B12 per day). Assigned. The doses recommended by the US and Taiwanese RDAs and the Adequate Intakes (AIs) recommended by the European Food Safety Authority (EFSA).
The intervention was conducted for 4 weeks. However, the actual B12 content of the seaweed used during the study was low, so the intake was changed to 1.9 μg and 3.1 μg for 5 g and 8 g of seaweed, respectively.
A panel of serum B12 markers was used to overcome the limitations of a single marker. These include serum vitamin B12, holotranscobalamin (holoTC), homocysteine (Hcy), methylmalonic acid (MMA), and their combined score, the 4cB12 score.
Dietary B12 content was measured at baseline and after 4 weeks using a customized food frequency questionnaire. Baseline measurements were used to calculate the least squares mean (LSM) of change in B12 levels over the study period.
Seaweed improves B12 levels
During the study period, dietary intake of B12 increased on average from 0.3 μg/day to 2.0 μg/day and from 0.5 μg/day to 3.5 μg/day in the low-dose and high-dose groups, respectively. Of the total, the contribution of Nori was 1.9 μg and 3.1 μg, respectively.
In both seaweed groups, all vitamin B12 biomarkers improved, with a consistent decrease in the prevalence of vitamin B12 deficiency post-study, in contrast to overall biomarker changes in the control group. I showed it.
Seaweed consumption increased serum B12, holo-TC, Hcy, and 4cB12 levels. Serum MMA levels remained constant among the three groups but improved in the low-dose group.
In the low-dose group, B12 levels increased to a stable level compared to controls. LSM was +59 pmol/L, holoTC increased by 28.2 pmol/L, and Hcy decreased by 3.7 μmol/L. 4cB12 score increased by 0.67.
Similar changes without further dose-dependent increases occurred in the high-dose groups of B12, Hcy, and 4cB12. No significant changes were observed in serum folate levels in any group.
The lack of a dose-response effect may be due to saturation of intrinsic factor (IF), which is involved in B12 absorption. Differences in B12 content per bag of seaweed may also have contributed, since year-round sampling ranged from 23.1 to 52.8 μg/100 g of seaweed. Still, all major seaweed brands contain at least 50% B12 RDA, indicating that this is a reliable source of B12.
Seaweed obviously produces B12, but fermented products and organic vegetables grown with manure-based fertilizers acquire B12 content through B12-producing foreign microorganisms and unexpected contamination.
Conflicting findings in other studies may be due to the inclusion of other sea vegetables and algae containing B12 analogs. A contributing factor may have been an error in the responses to the food frequency questionnaire, in which different types of sea vegetables were mixed up. Different processing techniques and fatigue due to consumption of more than 8 g of seaweed per day (the maximum in this study) are also potential sources of error.
conclusion
Ingestion of 5 g of seaweed per day for 4 weeks led to significant improvements in serum vitamin B12 levels, while no further increases were observed with higher intakes. These findings indicate that nori contains bioavailable B12 and no inhibitory B12 analogs. Other seaweeds, such as Wolffia globosa duckweed and Formosan nori, must be examined individually.
The increase in B12 compares to the increase achieved by adding milk, whey powder, B12-enriched toothpaste, or oral B12 supplements to a vegetarian or vegan diet. Still, the only previous study to show normal B12 levels in vegetarians is the Adventist Health Study-2 with the intake of fortified foods and supplements.
Increasing the frequency of consuming seaweed in combination with vitamin B12-fortified foods may enhance vitamin B12 absorption and avoid intake fatigue.
