Low-Carbohydrate Diet in Teens: 5 Main Surprising Findings

In the management of Type 1 Diabetes Mellitus (T1DM), diet plays a pivotal role, particularly for adolescents grappling with this chronic condition.

This article delves into the intricacies of a low-carbohydrate diet (LCD), a regimen that has gained attention for its potential benefits in blood sugar control.

However, the diet's impact on micronutrient intake – encompassing essential vitamins and minerals – is a subject of growing concern.

By focusing on this demographic, the article aims to shed light on the nutritional challenges and necessities that adolescents with T1DM face when adhering to a low-carbohydrate dietary plan.

Main Findings

• A significant decrease in carbohydrate intake after following the LCD.
• Reductions in BMI z-scores and waist circumference, indicating improvements in obesity indices.
• Decreased intake of several nutrients, including iron, calcium, vitamin B1, and folate, potentially leading to deficiencies.
• Improved glycemic control and reduced ultra-processed food consumption.
• The study highlights the need for careful nutritional monitoring when adopting LCD in adolescents with T1DM to avoid potential nutrient deficiencies.

Understanding Type 1 Diabetes

Low-Carbohydrate Diets in Type 1 Diabetes: A Balanced Perspective

Affecting many children, Type 1 Diabetes (T1DM) is a common metabolic condition with often unstable blood sugar levels A Trusted Source

Chiang, J.L.; Maahs, D.M.; Garvey, K.C.; Hood, K.K.; Laffel, L.M.; Weinzimer, S.A.; Wolfsdorf, J.I.; Schatz, D. Type 1 Diabetes in Children and Adolescents: A Position Statement by the American Diabetes Association. Diabetes Care 2018, 41, 2026–2044. [Google Scholar, CrossRef, Green Version].

Managing T1DM involves dietary therapy to promote better health, diabetes control, and reduced heart disease risk A Trusted Source

Gregory, J.W.; Cameron, F.J.; Joshi, K.; Eiswirth, M.; Garrett, C.; Garvey, K.; Agarwal, S.; Codner, E. ISPAD Clinical Practice Consensus Guidelines 2022: Diabetes in Adolescence. Pediatr. Diabetes 2022, 23, 857–871. [Google Scholar, CrossRef, PubMed].

A frequently used approach combines the Mediterranean diet with carbohydrate counting A Trusted Source

Gregory, J.W.; Cameron, F.J.; Joshi, K.; Eiswirth, M.; Garrett, C.; Garvey, K.; Agarwal, S.; Codner, E. ISPAD Clinical Practice Consensus Guidelines 2022: Diabetes in Adolescence. Pediatr. Diabetes 2022, 23, 857–871. [Google Scholar, CrossRef, PubMed].

Despite progress in medicine and nutrition, glycemic control remains challenging, with HbA1c averaging 9.3% for ages 15-18 A Trusted Source

Foster, N.C.; Beck, R.W.; Miller, K.M.; Clements, M.A.; Rickels, M.R.; DiMeglio, L.A.; Maahs, D.M.; Tamborlane, W.V.; Bergenstal, R.; Smith, E.; et al. State of Type 1 Diabetes Management and Outcomes from the T1D Exchange in 2016–2018. Diabetes Technol. Ther. 2019, 21, 66–72. [Google Scholar, CrossRef, PubMed].

Carbohydrates significantly impact blood sugar after meals.

International guidelines recommend 40-50% of total energy from carbohydrates, with precise insulin-carbohydrate matching A Trusted Source

Gregory, J.W.; Cameron, F.J.; Joshi, K.; Eiswirth, M.; Garrett, C.; Garvey, K.; Agarwal, S.; Codner, E. ISPAD Clinical Practice Consensus Guidelines 2022: Diabetes in Adolescence. Pediatr. Diabetes 2022, 23, 857–871. [Google Scholar, CrossRef, PubMed].

Currently, there isn't enough evidence to support low-carbohydrate diets (LCD) for T1DM A Trusted Source

Neuman, V.; Plachy, L.; Pruhova, S.; Kolouskova, S.; Petruzelkova, L.; Obermannova, B.; Vyzralkova, J.; Konecna, P.; Vosahlo, J.; Romanova, M.; et al. Low-Carbohydrate Diet among Children with Type 1 Diabetes: A Multi-Center Study. Nutrients 2021, 13, 3903. [Google Scholar, CrossRef, PubMed] A Trusted Source

Lennerz, B.S.; Barton, A.; Bernstein, R.K.; Dikeman, R.D.; Diulus, C.; Hallberg, S.; Rhodes, E.T.; Ebbeling, C.B.; Westman, E.C.; Yancy, W.S.; et al. Management of Type 1 Diabetes with a Very Low–Carbohydrate Diet. Pediatrics 2018, 141, e20173349. [Google Scholar, CrossRef, PubMed, Green Version].

However, some opt for LCD due to the difficulty in matching carbs with insulin, which can lower glycemic response and insulin needs.

But, endorsing LCD comes with dietary risks, as it involves avoiding healthy carb sources like whole grains, legumes, and fruits.

T1DM individuals may face risks such as diabetic ketoacidosis, hypoglycemia, and growth issues on LCD A Trusted Source

De Bock, M.; Lobley, K.; Anderson, D.; Davis, E.; Donaghue, K.; Pappas, M.; Siafarikas, A.; Cho, Y.H.; Jones, T.; Smart, C. Endocrine and Metabolic Consequences Due to Restrictive Carbohydrate Diets in Children with Type 1 Diabetes: An Illustrative Case Series. Pediatr. Diabetes 2018, 19, 129–137. [Google Scholar, CrossRef].

Adherence to restricted diets is tough and affects social life.

Those who choose LCD often do so without medical guidance, risking nutrient depletion A Trusted Source

Seckold, R.; Fisher, E.; de Bock, M.; King, B.R.; Smart, C.E. The Ups and Downs of Low-Carbohydrate Diets in the Management of Type 1 Diabetes: A Review of Clinical Outcomes. Diabet. Med. 2019, 36, 326–334. [Google Scholar, CrossRef].

Studies on LCD's impact on blood sugar are often lacking validated dietary data.

Behind the Scenes of the Study

This report presents a prospective clinical trial conducted at the Pediatric Endocrinology and Diabetes Unit, Sheba Medical Center.

The eligibility criteria included a T1DM diagnosis based on the American Diabetes Association criteria A Trusted Source

Chiang, J.L.; Maahs, D.M.; Garvey, K.C.; Hood, K.K.; Laffel, L.M.; Weinzimer, S.A.; Wolfsdorf, J.I.; Schatz, D. Type 1 Diabetes in Children and Adolescents: A Position Statement by the American Diabetes Association. Diabetes Care 2018, 41, 2026–2044. [Google Scholar, CrossRef, Green Version], age between 12 to 22 years, and the use of a continuous glucose monitoring device.

Participants with a history of eating disorders in themselves or their family members, as well as those with any other mental illness, were excluded due to concerns about the potential relationship between restrictive carbohydrate diets and eating disorders.

Written consent was obtained from participants aged 18 and older, and from parents or guardians for those under 18.

The study received ethical approval from the Helsinki Committee at the Sheba Medical Center.

At the outset, each participant underwent a cooking workshop and received an individualized low-carbohydrate diet (LCD) plan.

For participants under 18, both participants and their parents received nutrition education.

Participants had seven face-to-face meetings with a dietitian at weeks 1, 2, 4, 7, 10, 12, and 24, along with two 10-15 minute motivational phone calls within the first 12 weeks.

Throughout the study, participants had the option to consult with the study's dietitian.

The LCD aimed to provide 50-80 grams of carbohydrates per day without caloric restriction.

Each patient received a weekly meal and snack plan.

The planned macronutrient composition was 20% carbohydrates, 25% protein, and 55% fat, as detailed in the approved protocol.

The participants' usual dietary habits were assessed at baseline and after six months of intervention using the Food Frequency Questionnaire (FFQ).

The FFQ included 116 commonly consumed food items in Israel, along with portion sizes and frequency responses A Trusted Source

Shai, I.; Rosner, B.A.; Shahar, D.R.; Vardi, H.; Azrad, A.B.; Kanfi, A.; Schwarzfuchs, D.; Fraser, D. DEARR study Dietary Evaluation and Attenuation of Relative Risk: Multiple Comparisons between Blood and Urinary Biomarkers, Food Frequency, and 24-h Recall Questionnaires: The DEARR Study. J. Nutr. 2005, 135, 573–579. [Google Scholar, CrossRef, Green Version].

Total energy intake (Kcal), macronutrients, and micronutrients were calculated using the Tzameret software A Trusted Source

Ministry of Health Public Health Services Nutrition Division. Tzameret-Israeli National Nutrient Database 2015; Ministry of Health Public Health Services Nutrition Division: Jerusalem, Israel, 2015. and compared to dietary recommended intake (DRI) values A Trusted Source

Trumbo, P.; Schlicker, S.; Yates, A.A.; Poos, M.; Food and Nutrition Board of the Institute of Medicine, The National Academies. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids. J. Am. Diet. Assoc. 2002, 102, 1621–1630. [Google Scholar, CrossRef].

Data regarding age of diabetes onset, diabetes duration, and other medical diagnoses were collected from medical records.

Height, weight, waist circumference, and body mass index (BMI) A Trusted Source

Lumeng, J.C.; Kaciroti, N.; Frisvold, D.E. Changes in Body Mass Index z Score over the Course of the Academic Year among Children Attending Head Start. Acad. Pediatr. 2010, 10, 179–186. [Google Scholar, CrossRef, PubMed, Green Version] were measured at each visit following standardized protocols.

Blood samples, including HbA1c, cholesterol levels, C-reactive protein, and various mineral and vitamin levels, were collected at baseline and at 24 weeks under metabolic stability conditions and processed by ELISA at the Sheba Medical Center laboratories.

The primary endpoint of the study was the nutritional status of vitamins and minerals after 24 weeks on an LCD, while secondary outcomes included body weight and waist circumference at this time point.

The study's findings were analyzed using appropriate statistical tests, including the Wilcoxon test for continuous variables and Spearman's correlation coefficient for associations between continuous variables.

All statistical analyses were two-sided, and p-values were adjusted by the false discovery rate using SPSS software (IBM SPSS STATISTIC version 28, IBM Corp., Armonk, NY, USA, 2021).

Key Discoveries

In this study, twenty adolescents, predominantly female (14 out of 20), with Type 1 Diabetes (T1DM) participated.

They had a median age of 17 years and a median diabetes duration of 10 years.

Most of them (18 out of 20) were treated with insulin pumps.

The median BMI z-score was 1.3, categorized into normal weight (9 participants), overweight (7 participants), and obesity (4 participants).

One participant withdrew after 3 months due to difficulties in managing the low-carbohydrate diet (LCD).

Initially, their diet consisted of 44% calories from carbohydrates, 18% from protein, and 35% from fat.

Micronutrient percentages met or exceeded Dietary Recommended Intake (DRI) values, including fiber, iron, magnesium, calcium, zinc, copper, vitamin B1, vitamin B2, vitamin B6, vitamin B9 (folate), vitamin B12, and vitamin C.

After six months on the LCD, significant changes were observed.

The calorie percentage from carbohydrates dropped to 20%, protein intake increased to 25%, and fat consumption rose to 51%.

The total energy intake decreased significantly from 2537 kcal to 1533 kcal, and the proportion of calories from ultra-processed foods decreased from 16.6% to 11.0%.

Carbohydrate intake dropped by 67%, from 265.0 g to 86.6 g, leading to reductions in fibers, total sugars, and fructose.

Protein intake decreased but remained within the DRI.

Fat intake remained relatively stable.

Several minerals and vitamins showed significant decreases, with iron, calcium, vitamin B1, and folate falling below recommended values.

Some fat-soluble vitamins (A, E, K) and vitamin C showed moderate decreases but were not statistically significant.

According to DRI, more participants were deficient in fiber, calcium, magnesium, copper, vitamin B1, and folate after the intervention compared to before.

The LCD was associated with reduced BMI z-scores and waist circumference percentiles.

HbA1c levels decreased from 8.1% to 7.7%.

Lipid profile parameters remained stable, while CRP levels decreased.

Some participants showed low magnesium, folic acid deficiency, and marginal vitamin C levels.

Serum zinc levels decreased but stayed within the normal range.

Vitamin B1, calcium, and phosphorous levels remained relatively stable.

The study found correlations between decreased carbohydrate intake and reduced intake of fibers, iron, copper, potassium, magnesium, vitamin B1, vitamin B6, vitamin B2, and vitamin C. Decreased protein intake correlated with reduced intake of fat, iron, calcium, potassium, sodium, zinc, vitamin B1, and vitamin B2.

No significant correlations were found between reported dietary intake and blood levels of calcium, magnesium, thiamine, and vitamin C.

What This Means for You

In a groundbreaking study involving adolescents with Type 1 Diabetes (T1DM), researchers examined the effects of a Low-Carbohydrate Diet (LCD) over six months.

Their findings shed light on the impact of LCD on macronutrients, micronutrients, and various health parameters among these individuals.

Key Findings:

• Carbohydrate Intake Reduced Significantly:

The study participants demonstrated remarkable compliance with the LCD, reducing their carbohydrate intake by 70%.

This decrease was associated with lower consumption of fibers and fructose, which aligns with similar findings in studies exploring LCD's effects A Trusted Source

De Bock, M.; Lobley, K.; Anderson, D.; Davis, E.; Donaghue, K.; Pappas, M.; Siafarikas, A.; Cho, Y.H.; Jones, T.; Smart, C. Endocrine and Metabolic Consequences Due to Restrictive Carbohydrate Diets in Children with Type 1 Diabetes: An Illustrative Case Series. Pediatr. Diabetes 2018, 19, 129–137. [Google Scholar, CrossRef] A Trusted Source

Gardner, C.D.; Landry, M.J.; Perelman, D.; Petlura, C.; Durand, L.R.; Aronica, L.; Crimarco, A.; Cunanan, K.M.; Chang, A.; Dant, C.C.; et al. Effect of a Ketogenic Diet versus Mediterranean Diet on Glycated Hemoglobin in Individuals with Prediabetes and Type 2 Diabetes Mellitus: The Interventional Keto-Med Randomized Crossover Trial. Am. J. Clin. Nutr. 2022, 116, 640–652. [Google Scholar, CrossRef, PubMed] A Trusted Source

Storz, M.A.; Ronco, A.L. Nutrient Intake in Low-Carbohydrate Diets in Comparison to the 2020–2025 Dietary Guidelines for Americans: A Cross-Sectional Study. Br. J. Nutr. 2022, 129, 1023–1036. [Google Scholar, CrossRef, PubMed].

• Fat Intake Remained Stable:

Contrary to concerns about increased fat consumption on LCD, fat intake among the participants remained relatively constant as a percentage of total calories.

This stability was due to the overall decrease in calorie consumption A Trusted Source

Schmidt, S.; Christensen, M.B.; Serifovski, N.; Damm-Frydenberg, C.; Jensen, J.-E.B.; Fløyel, T.; Størling, J.; Ranjan, A.; Nørgaard, K. Low versus High Carbohydrate Diet in Type 1 Diabetes: A 12-Week Randomized Open-Label Crossover Study. Diabetes Obes. Metab. 2019, 21, 1680–1688. [Google Scholar, CrossRef].

• Micronutrient Intake Declined:

Despite initial nutrient-rich profiles, the participants' intake of several essential micronutrients, including iron, calcium, phosphorus, and vitamin B1, decreased significantly A Trusted Source

Churuangsuk, C.; Griffiths, D.; Lean, M.E.J.; Combet, E. Impacts of Carbohydrate-restricted Diets on Micronutrient Intakes and Status: A Systematic Review. Obes. Rev. 2019, 20, 1132–1147. [Google Scholar, CrossRef, PubMed].

These declines were consistent with other research on carbohydrate-restricted diets and highlight the importance of monitoring nutrient intake.

• Vitamins and Minerals Vital for Health:

The study underscored the significance of B vitamins, which play crucial roles in cellular metabolic pathways and neurotransmitter synthesis.

It also emphasized the importance of calcium, magnesium, and other minerals for overall well-being.

• Metabolic Improvements:

On a positive note, the study revealed several metabolic improvements among the participants, including reduced BMI z-scores, waist circumference percentiles, and CRP levels.

HbA1c levels, an important marker of glycemic control, also improved A Trusted Source

Grabia, M.; Markiewicz-Żukowska, R.; Socha, K. Prevalence of Metabolic Syndrome in Children and Adolescents with Type 1 Diabetes Mellitus and Possibilities of Prevention and Treatment: A Systematic Review. Nutrients 2021, 13, 1782. [Google Scholar, CrossRef].

• Nutritional Guidance for LCD:

The research findings emphasize the need for long-term monitoring of individuals with T1DM who adopt LCD.

Nutritional deficiencies that may arise during LCD adherence underscore the importance of providing substitutes to bridge these gaps A Trusted Source

Liu, Y.-M.C.; Williams, S.; Basualdo-Hammond, C.; Stephens, D.; Curtis, R. A Prospective Study: Growth and Nutritional Status of Children Treated with the Ketogenic Diet. J. Am. Diet. Assoc. 2003, 103, 707–712. [Google Scholar, CrossRef].

• Study Limitations:

While the study provides valuable insights, it has some limitations.

The dietary recall method used may be subject to recall bias, although it is considered more reliable than single-day recall A Trusted Source

Grandjean, A.C. Dietary Intake Data Collection: Challenges and Limitations. Nutr. Rev. 2012, 70 (Suppl. S2), S101–S104. [Google Scholar, CrossRef, PubMed].

Additionally, the study cohort was relatively small, and the impact of LCD over an extended period was not explored.

Further research is needed to gain a comprehensive understanding of the long-term effects of LCD on individuals with T1DM.

In summary, this study contributes significantly to our understanding of how LCD impacts the nutrient intake and health parameters of adolescents with T1DM.

While LCD offers potential benefits for glycemic control and metabolic health, it is crucial to address the associated nutritional challenges to ensure the overall well-being of individuals following this dietary approach.

Final Thoughts

Low-Carbohydrate Diets for Type 1 Diabetes: Nutritional Considerations

In diabetes care, medical nutrition therapy is pivotal A Trusted Source

Gregory, J.W.; Cameron, F.J.; Joshi, K.; Eiswirth, M.; Garrett, C.; Garvey, K.; Agarwal, S.; Codner, E. ISPAD Clinical Practice Consensus Guidelines 2022: Diabetes in Adolescence. Pediatr. Diabetes 2022, 23, 857–871. [Google Scholar, CrossRef, PubMed].

Low-carbohydrate diets (LCD) show promise in enhancing glycemic control and addressing issues like obesity and metabolic syndrome.

However, opting for LCD may bring about nutritional deficiencies.

Studies indicate that reduced carbohydrate intake correlates with decreased vitamin and mineral consumption, unrelated to calorie reduction but due to the nature of LCD.

Therefore, when individuals with Type 1 Diabetes consider LCD, it's crucial to assess their vitamin and mineral intake from the outset.

Dietitians should design plans that include foods rich in soluble vitamins (especially folate and thiamin), selenium, magnesium, calcium, and iron.

Specific quantities of supplements like yeast extract, Brazil nuts, and Wolffia globose may be recommended.

Regular monitoring of vitamin and mineral blood levels every six months is advisable.

Supplementation may be necessary to meet daily intake requirements for these essential nutrients.

The shift to LCD can offer benefits, but careful attention to nutrient intake is essential to maintain overall health for those with Type 1 Diabetes.

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