Palmitoleic Isomer Study
Condition: Insulin Sensitivity
MeSH terms: Insulin Resistance
Study type: Interventional

Summary: 
      Trans-palmitoleic acid (trans-C16:1) is a naturally occurring trans fatty acid present in
      small quantities in foods, most notably in dairy products. Observational evidence suggests a
      positive association between trans-C16:1 and insulin sensitivity, and negative association
      with risk of developing type 2 diabetes mellitus [1-3]. Cis-palmitoleic acid (cis-C16:1) is
      found naturally in foods and is particularly high in macadamia nuts and oil extracted from
      the sea buckthorn plant. Animal models suggest that this palmitoleic acid isomer also
      improves insulin sensitivity and reduces metabolic dysfunction.

      This pilot dosing study is necessary to inform the design of a larger trial to test the
      hypothesis that both trans-C16:1 and cis-C16:1 improve insulin resistance but at different
      doses. Plasma phospholipid fatty acid profiles will be used as the primary outcome measure.
    

Detailed description: 
      The fatty acids trans-C16:1 and cis-C16:1 have been associated with healthy plasma glucose
      levels. Elevated glucose levels have been associated with diabetes. This study is designed to
      determine whether there is a dose-response relation between how much trans-C16:1 and
      cis-C16:1 you consume and how much appears in plasma. This information will be used to design
      a future study to determine whether trans-C16:1 and cis-C16:1 could be used to treat
      diabetes. Trans-C16:1 occurs naturally in dairy fat such as milk and cheese, while cis-C16:1
      occurs naturally in nuts, particularly, macadamia nuts, and a plant called sea buckthorn. The
      study will consist of two 9-week phases, with a minimum of a 4 week off-study period between
      the two phases. Fasting blood will be drawn at baseline (first day of week 1), 3 weeks, 6
      weeks and 9 weeks (4 total blood draws per phase or 8 total blood draws for 2 phases). During
      each phase you will be asked to consume increasing numbers of vegetable oil capsules, 2 per
      day during the first 3 weeks, 4 per day during the second 3 weeks, and 8 per day during the
      third 3 weeks. During each of these periods you should take half the capsules in the morning
      and half in the evening, with your meals. You will be randomly assigned to receive the
      trans-C16:1 or cis-C16:1 during the first phase and the other during the second phase. The
      total length of the study is about 18 weeks, not including the break between phase 1 and
      phase 2 (not less than 4 weeks). The trans-C16:1 in the capsules will be in the form of
      partially-hydrogenated soybean oil. The cis-C16:1 in the other capsules will be in the form
      of sea buckthorn oil.
    

Intervention name(s): Trans-C16:1 supplement; Cis-C16:1 supplement
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Each volunteer will consume 3 escalating doses (120 mg/day, 240 mg/day and 480 mg/day) of trans-C16:1 enriched vegetable oil for 3 weeks each (3 doses x 3 weeks each [9 weeks total]; Each volunteer will consume 3 escalating doses (380 mg/day, 760 mg/day and 1520 mg/day) of cis-C16:1 enriched vegetable oil for 3 weeks each (3 doses x 3 weeks each [9 weeks total]
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Other
Keywords: cis-C16:1n7 supplement; trans-C16:1n7 supplement; palmitoleic acid supplement