Low Carbohydrate/High Protein Diet to Improve Metabolic Health
Condition: Spinal Cord; Metabolic Syndrome; Diabetes
MeSH terms: Metabolic Syndrome
Study type: Interventional

Summary: 
      Individuals with spinal cord injury (SCI) are living to ages when metabolic disorders are
      highly prevalent. The combination of impaired glucose tolerance and insulin resistance can
      disrupt lipid metabolism and increase the risk of cardiovascular disease and diabetes, and
      contribute to an accelerated aging process in the SCI population. Feasible interventions to
      improve metabolic function in the chronic SCI are in great demand. Compared to pharmacologic
      therapies, dietary modification is a more cost-effective treatment option for reducing the
      risk of metabolic dysfunction that, surprisingly, has not been rigorously investigated in
      people with SCI. Therefore, in the present study the investigators will investigate the
      efficacy of an 8-week, eucaloric (a meal plan designed specifically to provide the exact
      amount of calories needed to maintain a given body weight) LC-HP dietary intervention for
      improving metabolic function, body composition, gut bacteria composition and quality of life
      in individuals with SCI and impaired glucose tolerance or type 2 diabetes. The investigators
      also aim to determine the association between changes in the composition of gut bacteria and
      improvements in metabolic function and the association between improvements in metabolic
      function and improvements in quality of life.
    

Detailed description: 
      Individuals with spinal cord injury (SCI) are living to ages when metabolic disorders are
      highly prevalent. Due to the loss of mobility and severe skeletal muscle atrophy in
      individuals with SCI, obesity, impaired glucose tolerance, and peripheral insulin resistance
      develop after injury . The combination of impaired glucose tolerance and insulin resistance
      can disrupt lipid metabolism and increase the risk of cardiovascular disease and diabetes,
      and contribute to an accelerated aging process in the SCI population. Because of these
      trends, the overall burden of health complications and their economic impact has increased
      for individuals with SCI, often leading to a progressive decrease in their long-term quality
      of life. Feasible interventions to improve metabolic function (i.e. the way the body
      processes proteins, carbohydrates, and fats in foods) in those with chronic SCI are in great
      demand. Given that metabolic disorders severely compromise health outcomes and important
      domains of quality of life, including participation in daily life and community living and
      employment outcomes, targeted strategies to combat these morbidities are of paramount
      importance. Compared to pharmacologic therapies, dietary modification is a more
      cost-effective treatment option for reducing the risk of metabolic dysfunction that,
      surprisingly, has not been rigorously investigated in people with SCI. Much like the general
      U.S. population, individuals with SCI consume far more fat and carbohydrate than recommended
      levels. High fat, high carbohydrate diets (western diet) have been associated with a higher
      prevalence of obesity and metabolic disease as well as negative adaptations in the diversity
      of gut bacteria (increased levels of harmful bacteria and reduced levels of beneficial
      bacteria) that usually precedes the development of diabetes or insulin resistance. Therefore,
      macronutrient (carbohydrate, protein, and fat) modification may be able to prevent or correct
      the impaired metabolic state in persons with SCI. Diets composed of relatively high protein
      and low carbohydrate have been shown to improve body composition (i.e., reduce body fat while
      maintaining lean tissue) and metabolic profiles (i.e., increase in insulin sensitivity and
      glucose tolerance) in diabetic, able bodied individuals who are obese or overweight. This
      improvement is thought to be due to protein's: (i) effect on the sensation of feeling full
      after eating food despite similar or lower energy intake; (ii) contribution to storage of
      fat-free mass; and (iii) insulin sensitizing effect.

      The investigators' pilot work supports this hypothesis in that we showed that 8 weeks of a
      low carbohydrate/high-protein (LC-HP) diet significantly improved whole body insulin
      sensitivity (WBIS) and glucose tolerance and decreased the amount of intra-abdominal fat in
      six men with SCI and with either untreated type 2 diabetes or impaired glucose tolerance
      (pre-diabetes). In addition to significant improvements in metabolic health, our pilot work
      also successfully demonstrated the safety and feasibility of our approach. The lack of
      adverse effects and the improvement in glucose control and insulin sensitivity in our study
      participants with SCI prompted us to propose the current study involving both men and women
      in order to determine the effects of the dietary protocol to treat type 2 diabetes or
      impaired glucose tolerance in persons with chronic SCI. Thus, the investigators propose an
      investigation to determine if 8 weeks of an LC/HP dietary intervention induces the
      physiological adaptations necessary to improve metabolic function and body composition and
      alter the diversity of gut bacteria in a large cohort of individuals with SCI. The ultimate
      outcome of this project will be an effective diet program which can be easily and
      economically implemented at home as a non-pharmacological means of achieving blood glucose
      control for people with SCI and impaired glucose tolerance or untreated type 2 diabetes.
    

Intervention name(s): LC/HP
Intervention type(s): Other
Intervention description(s): Intervention group will receive 8 weeks of LC/HP diet. The daily LC-HP dietary intervention will include ~30% total energy as protein (1.6 g/kg per day) with a carbohydrate-to-protein ratio <1.5 and fat intake set at ~30% of the total energy intake.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Other
Keywords: SCI; High Protein; Low Carbohydrate; Metabolic Health; Microbiome