Emerging Trends in Nutrition: Understanding Today's Popular Diets as they Relate to Diabetes
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Emerging Trends in Nutrition: Understanding Today’s Popular Diets as they
Relate to Diabetes
Jennifer Sygo, M.Sc., RD Registered Dietitian and Sports Nutritionist, Cleveland Clinic Canada
Nutrition Columnist, National Post Author, “Unmasking Superfoods” (HarperCollins Canada 2014)
…as recently as 10 years ago…
1Moore et al, Cochrane Database Syst Rev. 2004;CD004097.
…and 6 years ago…
1Nield et al, Cochrane Database Syst Rev. 2008;CD005102.
Times have changed…
• Now have numerous contenders: low carb, low GI, Mediterranean, Paleo, vegetarian/vegan
• Ajala (2013): 1st systematic review & meta-analysis1
1Ajala, Am J Clin Nutr. 2013 (97):505.
Comparing Diets
• Low-GI for glycemic control: Jenkins (2008), Ma (2008), Wolever (2008)
• Mediterrean: Elhayany (2010), Esposito (2008), Toobert (2003)
• High protein: Brinkworth (2004), Larsen (2011)
…all suggest some benefit vs. standard diet recommendations and/or typical Western diet
How about low-carb?
• Can be low carb, high protein, or low carb, high fat (LCHF)
• Composition varies, but typically: – Reduce from ~275 g/day intake (based on 2000
kcal/day and 55% of calories from CHO) – To “lower CHO” (120 g/day or 40% kcal = Zone) – Or “low CHO” as low as 20 g CHO/day (induction
phase of Atkins)
Compare: 20-25 g CHO = ½ cup cooked pasta, 1/3 bagel, 1 slice bread, 1/3 cup cooked rice, 1 banana, 1 cup fruit juice
Low-carb vs. other diets in type 2 DM
Samaha, Haimoto, Davis, Iqbal compared to low fat Westman, Wolever-1 compared to low GI Elhayany-1 compared to Mediterranean Stern compared to high CHO
Ajala, Am J Clin Nutr. 2013 (97):505.
What about ketogenic diets?
• Duke study (2008): LCHF ketogenic diet vs. cutting kcal by 500/day (low GI) in type 2 DM for 6 months:1
• LCHF lost 24.5 lbs vs. 15.2 lbs in low GI; • HbA1C -1.5% vs. -0.5%; • 92% vs. 62% reduced or eliminated diabetic meds
• Yamada (2014): LCHF (keto or not) vs. kcal-controlled in type 2 DM for 6 months2
1Nutr Metab (Lond). 5:36, 2008. 2Intern Med. 53:13, 2014.
Intern Med. 53:13, 2014.
Intern Med. 53:13, 2014.
And the latest contender: Paleo Diet
• Aka Paleolithic, caveman, Stone Age, hunter-gatherer diet • Paleo period: 2.5 million years ago w/ start of use of stone
tools; ended 10,000 years ago w/ advent of agriculture • Premise: our genomes have not changed (significantly) in
~500 generations since this time; thus, we are better adapted to the diet and lifestyle of the Paleo period than now
Paleo Diet Principals INCLUDED EXCLUDED
Meats and/or game, preferably grass-fed Processed foods of any kind
Fish, preferably wild Processed oils (corn, sunflower, etc.)
Eggs Added sugar
Fruits (whole/unprocessed) Added salt
Vegetables (whole/unprocessed) Grains of all kinds, including ancient
Nuts (not peanuts) Cereals and pseudocereals
Seeds Dairy, including goat’s milk
Also: some oils, e.g. olive, macadamia nut Beans, lentils, pulses/legumes
Sprouted grains/legumes Alcohol (more than 3 drinks/week)
Paleo Diet Evidence? AUTHOR POPULATION INTERVENTION CONTROL OUTCOME O’Dea et al (1980)
13 healthy Australian Aborigines
3 month Paleo diet None Improved insulin response to CHO; no change in glucose among non-diabetics
O’Dea et al (1984)
10 Australian Aborigines w/ type 2 DM
7 wks Paleo diet None 10% wt loss; fasting blood sugar, insulin levels, triglycerides (TG) improved
Lindeberg et al (2007); Jonsson et al (2010)
29 pts w/ ischemic HD & IGT or T2DM
12 wk Paleo diet (randomized)
12 wks Mediter-ranean diet (low fat dairy, margarines)
Glucose tolerance improved more in Paleo diet, even independent of wt loss; Paleo diet consumed 1380 kcal vs. 1809 MJ/d, but felt equally full; appetite hormones improved more in Paleo
Osterdahl et al (2008)
14 healthy subjects
3 wk Paleo diet None Decreased weight, waist circumference (WC), systolic BP
Jonsson et al (2009)
13 T2DM 3 month Paleo (cross-over)
Diabetes diet Decr. wt, WC, 3-month blood sugar, TG, diastolic BP; Increased HDL in Paleo vs. Diabetes Diet
Frassetto et al (2009)
9 nonobese, sedentary, healthy
10 d. Eucaloric Paleo diet
None Total cholesterol (-0.8 mmol/L), LDL chol (-0.7 mmol/L), TG (-0.3 mmol/L) all improved
Paleo Diet: the Jonsson Study (2009)
• Pilot cross-over study comparing ad libitum “Diabetes Diet” of vegetables, root vegetables, whole grain breads and cereals, fruits/berries; lower fat and higher monounsaturated fat; vs. “Paleo”: lean meat, fish, fruit, vegetables, eggs, nuts in 13 type 2 diabetics on medication
• Diabetes Diet included instruction re: glycemic index, meal-planning plate model, sodium reduced
• No advice on proportions of different foods, but rationale, potential benefits for both diets were explained
• Paleo diet: lower intake of calories, carbs, glycemic load, fibre, saturated fat, cholesterol
• Study terminated due to inability to recruit any new participants after 6 mos.
The Best of Paleo? • Protein • Fats • Nuts & Seeds • Fruits & Vegetables
ON THE OTHER HAND: • Humans have evolved on myriad different diets • Common thread is no processed foods, added sugar,
salt, etc. • While grains, dairy, legumes may not be essential parts
of our diet – does that mean they must be excluded? • Let’s take the best concepts until the research tells us
more
Other Nutrition Trends to Consider…
• Coconut • Full-fat milk/dairy • Foods that affect gut health/microbiome
Coconut: What’s in it?
Serving Size: 1.5 oz/45 g (2” x 2” chunk)
Calories 159
Fat 15 g
Saturated Fat 13 g
Sugar 3 g
Fibre 4 g
Protein 3 g
Iron 6%
Potassium 160 mg
Serving Size: 1 Tbsp (14 g/15 ml)
Calories 116
Fat 14 g
Saturated Fat 12 g
Sugar 0 g
Fibre 0 g
Protein 0 g
Iron 0%
Potassium 0 mg
COCONUT MEAT COCONUT OIL
Coconut
• Source of MCT • May promote weight loss when substituted
for equal kcal foods • BUT! High kcal (120 kcal/Tbsp). And can raise
LDL-C • BUT! Tends to be small, dense LDL, not large,
fluffy1
1J Nutr. 2003 Jan;133(1):78-83.
Full-Fat Dairy
• Debate as to effect of dairy-derived SFA on CVD risk1,2,3
• Most recently: 8 (!) svg of full-fat dairy/day associated with 23% lower risk of type 2 DM vs. lowest intake
• What is the mechanism of action? Or did we have it wrong all along?
1Br J Nutr. 2013 Jun 12;1-8. 2Eur J Epidemiol. 2011 Aug;26(8):609-18.
3J Nutr. 2013 Jan;143(1):74-9.
Microbiome
• Gut interacts with many other systems in the body
• Endotoxins may influence inflammation • May play a significant role in type 2 DM
(inflammation…more?)1, 2
• And, of course, that study on artificial sweeteners…3
1Alokail, Trials. 2013:14:195. 2Nitert, BMC Pregnancy Childbirth. 2013:13:50.
Suez, Nature. 2014 [Epub ahead of print]
Why the Confusion? “As a long-time subscriber, here’s what I think. I love the nutritionist’s column. It’s always interesting, though I know a couple of months later she’ll totally rescind everything she said before. Very funny.” The next time you read something about nutrition that seems contradictory, keep a few of these points in mind: 1. Nutrition, like all aspects of science and medicine, is an evolving area of
study. 2. It is difficult to assess the impact of a single nutrient on our health. 3. The endpoints of nutrition research can be difficult to define. 4. The findings of one study are exactly that. Bias is an inherent risk in all
research. Multiple studies need to be conducted by different research groups to determine whether a single finding is valid.
5. The findings of a study do not necessarily translate across the entire population.
Why the Confusion? Despite the confusion, there are some “truths” that have evolved, e.g.:
• Food is more complex and more valuable than individual nutrients. And, by extension, diets based on nutrient-dense whole foods are increasingly being shown to be the most healthful.
• There is a U-shaped curve for many, if not most aspects of nutrition.
• The placebo effect is strong. • We tend to create our own narratives about health (and
life) that influence the way we interpret things we read, hear and experience (“confirmation bias”).
• There is more to nutrition than nutrition.
The Bottom Line
If in doubt, eat your vegetables. Everything else is controversial.
The Bottom Line
But always, always, enjoy your food!
Thank You!
www.jennifersygo.com
Twitter: @JenniferSygo
jsygo@rogers.com
www.clevelandclinic.ca
www.nationalpost.com
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