A Pilot Pre and Post 4 Week Intervention Evaluating the Effect of a Proprietary, Powdered, Plant Based Food on Micronutrient Status, Dietary Intake, and Markers of Health in a Healthy Adult Population

Abstract

Background: A "balanced, adequate, and varied diet" is recommended as the basis of nutritionally sound diet by the World Health Organisation and national public health agencies. Huel is a proprietary, on-the-go, powdered, plant based food, providing all 26 essential vitamins and minerals, protein, essential fats, carbohydrate, fibre, and phytonutrients.

Objectives: Assessing the effect of solely consuming Huel on micronutrient status, dietary intake and markers of health was achieved through a 4-week intervention of solely Huel powder.

Methods: Habitual energy intake was assessed through a one-week lead in period with healthy adult participants (aged 18 or over) logging their food intake, after which only Huel was consumed for 4 weeks. Blood samples and body composition was assessed before and after the lead in week as well the end of the intervention. Thirty participants were recruited with 20 (11 females, median age 31, range 22-44) completing the study, 19 sets of blood samples were collected. 22 blood markers were analysed along with weight, BMI, waist circumference, visceral adipose tissue (VAT), and body composition. All blood micronutrients, except for Thyroid Stimulating Hormone and choline were sent to Royal Victoria Infirmary NHS, Newcastle Laboratory (Newcastle upon Tyne, United Kingdom) for analysis.

Results: Fourteen of the parameters significantly changed over the course of the study with circulating haemoglobin, iron, vitamins B12 and D as well as selenium significantly increasing (p < 0.05). HbA1c, total and non-HDL cholesterol, vitamins A and E, potassium, BMI, VAT, and waist circumference all significantly decreased (p < 0.05) post intervention.

Conclusion: Although energy intake decreased during the intervention period, the adherence to recommended micronutrient intake, as quantified by the dietary Total Adherence Score, significantly increased which tallies with the preservation or improvement of micronutrient status. This study potentially demonstrates that consuming only Huel for 4 weeks does not negatively affect micronutrient status.

Keywords: Huel; intervention study; micronutrient; micronutrient status; vitamin status.

FIGURE 1

CONSORT diagram and list of blood biomarkers assessed at each of the three visits. The two participants who withdrew at the second visit were due to failed phlebotomy. Of the eight who withdrew before the third visit two gave no reason, two had difficulty maintaining diet, one due to mood changes, one due to stomach issues, and two due to headaches.

FIGURE 2

Concentration of circulating haemoglobin l and iron ¢; for the 19 participants who completed the study. The mean of each measurement shown as a solid black line. There were statistical increases for both haemoglobin and iron from week 1 to week 5.

FIGURE 3

Total Cholesterol (•), Non-HDL Cholesterol (|), HDL cholesterol (✖), for the 19 participants who completed the study. The mean of each measurement shown as a solid grey line for total cholesterol and a solid black line for non-HDL cholesterol and HDL cholesterol.

FIGURE 4

HbA1c for the 19 participants who completed the study. The mean of each measurement shown as a solid black line.

FIGURE 5

Circulating vitamin A (•) and vitamin E (○) for the 19 participants who completed the study. The mean of each measurement shown as a solid black line.

FIGURE 6

Circulating vitamin D for the 19 participants who completed the study. The mean of each measurement shown as a solid black line.

FIGURE 7

Circulating vitamin B12 for the 19 participants who completed the study. The mean of each measurement shown as a solid black line.

FIGURE 8

Circulating selenium for the 19 participants who completed the study. The mean of each measurement shown as a solid black line.

FIGURE 9

Circulating potassium for the 19 participants who completed the study. The mean of each measurement shown as a solid black line.

FIGURE 10

Changes in micronutrient/energy intake based on food diary data over the course of the study. Bars in blue show micronutrient/energy intake from the baseline week with bars in orange showing micronutrient/energy intake from Huel diet only.

FIGURE 11

BMI of participants at the three timepoint measured during the trial. Week 1 represents a second measurement after a control week of normal diet. Week 5 represents a third measurement after 4 weeks of a 100% Huel diet. There was a significant difference between weeks 0 vs. 5 and 1 vs. 5. Asterisks denote statistical differences between means.

FIGURE 12

Visceral adipose tissue (VAT) of participants throughout the trial. Week 1 represents a second measurement after a control week of normal diet. Week 5 represents a third measurement after 4 weeks of a 100% Huel diet. The mean VAT of all the participants who completed the trial, with asterisks denoting statistical differences.

FIGURE 13

Change in waist circumference of participants throughout the trial as compared to Week 0. Week 1 represents a second measurement after a control week of normal diet. Week 5 represents a third measurement after 4 weeks of a 100% Huel diet.