Master 7 healthy oil use tips for diabetes prevention

Many individuals managing high blood pressure, cholesterol, or sugar (the "three highs") opt for healthier cooking oils. However, even a common choice like olive oil may fail to effectively control these conditions if used incorrectly. A nutritionist shares 7 methods for healthy oil use to help easily manage the three highs and prevent diabetes.

Nutritionist Sit Hiu-ching explained on her Facebook page that many office workers and individuals with the three highs believe they are using oil healthily—for instance, using only vegetable oil at home, adding coconut oil to coffee daily for perceived weight loss, or specifically choosing oils with high smoke points for stir-frying, assuming this protects blood vessels. Yet, annual check-ups often show cholesterol, triglyceride, and blood sugar levels creeping up year after year. She cites multiple studies indicating that the core issue often lies not in the oil itself, but in the overall oil strategy, including the choice of fatty acid types, pairing cooking temperatures and methods, and achieving a balanced ratio of Omega-3 to Omega-6.

1. Replace High Saturated Fat Sources

For those with the three highs or diabetes, the primary goal isn't blindly following specific oils, but examining the daily fat structure—whether it's dominated by saturated or unsaturated fats. Scientific evidence shows:

• A 2024 study in Advances in Nutrition indicated that replacing high-saturated-fat oils like coconut and palm oil with vegetable oils rich in mono- and polyunsaturated fats (e.g., olive, canola, rice bran oil) significantly lowers total and "bad" LDL cholesterol, with triglycerides also potentially decreasing. The same study noted that while coconut oil might slightly raise "good" HDL cholesterol, the increase in LDL is more pronounced, overall raising cardiovascular risk.
• The key is substituting rather than adding oils.

2. High Smoke Point ≠ Absolute Safety

Many choose oils believing a higher smoke point ensures safety for high-heat stir-frying or repeated deep-frying. Scientific findings reveal:

• A 2024 study in Foods, comparing various Omega-rich vegetable oils at 180-230°C, found that oils higher in polyunsaturated fats degraded more easily at high temperatures, with their polyunsaturated content decreasing while saturated and trans fats increased. Conversely, oils like high-oleic sunflower oil, higher in monounsaturated fats, showed better resistance to thermal breakdown.
• A 2025 study in Foods on extra virgin olive oil (EVOO) noted that smoke point only indicates when smoke appears, not the full extent of harmful compound formation during heating. Data from olive oil institutions shows that EVOO, while not having an exceptionally high smoke point, generates lower levels of trans fats and polar oxidation products at around 180°C compared to some refined oils with higher smoke points, thanks to its rich antioxidant content (polyphenols, Vitamin E).

3. The Key to Seed Oils & Nuts Causing Inflammation is Omega-3 Sufficiency

Online claims often label seed oils and nuts as inflammatory, leading many to discard oils like soybean or sunflower oil and avoid nuts. Scientific evidence clarifies:

• A 2025 review by the Academy of Nutrition and Dietetics indicated that, with controlled total calories and weight, replacing some saturated fat with seed oils (sunflower, canola, soybean) is associated with lower risks of cardiovascular events and all-cause mortality.
• A 2024 study in Frontiers in Nutrition using US NHANES data found no clear trend linking higher dietary Omega-6 intake with increased inflammatory markers. Conversely, with sufficient Omega-3 intake, both Omega-3 and Omega-6 were associated with lower systemic inflammation markers.
• A 2024 eLife study tracking ~85,000 adults in the UK Biobank found those with the highest blood plasma Omega-6 to Omega-3 ratio had higher all-cause and cardiovascular mortality risks than the lowest ratio group. However, increased concentrations of either Omega-3 or Omega-6 individually were linked to lower mortality risk, with Omega-3 offering stronger protection.
• A 2023 Nature Communications study on dietary fats and gut microbiota showed that high saturated fat diets promote a pro-inflammatory gut environment, while moderate intake of poly- and monounsaturated fats paired with high-fiber foods is more gut-friendly.

4. Omega-3 Helps Lower Triglycerides, Especially for Diabetics with High Triglycerides

For many diabetics, triglycerides are a troubling lab result. Beyond controlling total calories, sugar, and weight, fat composition is crucial. Evidence shows:

• In a 2025 Med study's randomized controlled trial on 309 type 2 diabetes patients with high triglycerides, daily supplementation of 4g fish oil (EPA/DHA) for 12 weeks reduced serum triglycerides by over 25% compared to a corn oil control group. The fish oil group also showed increased blood levels of EPA/DHA. The study noted that individual gut microbiota differences influenced the triglyceride reduction, indicating an interaction between Omega-3 metabolism and gut environment.

Nutritionist's 7 Tips for Healthy Oil Use to Easily Lower Three Highs & Prevent Diabetes

SIt outlines 7 methods to simply categorize and integrate oils into daily cooking, mastering the key to healthy oil use:

1. Primary Cooking Oil: Choose oils high in monounsaturated fats (e.g., olive, canola oil) for daily frying, stir-frying, and stewing. These help regulate blood lipids and improve insulin sensitivity.
2. Cold Dressings & Finishing Drizzle: Use flaxseed or pecan oil. Ideal for drizzling on salads, blanched vegetables, or soups after cooking to obtain plant-based Omega-3 and preserve natural antioxidants.
3. Flavor-Enhancing Oil: For aromatic oils like sesame or peanut oil, add 1 tsp just before serving to enhance flavor, avoiding prolonged high-heat cooking. This preserves their polyunsaturated fats. Common sesame oil is often high-heat roasted, and fragrant oil is often a blend; use less frequently or opt for cold-pressed versions.
4. High Saturated Fat Oils: Reserve coconut oil and butter for occasional use, not daily. Use sparingly in desserts or specific dishes. Allow most saturated fat intake to come from quality meats and dairy, avoiding accumulation from multiple sources.
5. Omega-3 Sources: Prioritize deep-sea fish, consuming 2-3 times weekly. For oils, complement with small amounts of cold-pressed plant oils, beneficial for gut microbiota balance and anti-inflammation.
6. Control Oil Quantity, But Avoid Oil-Free Diets: While oils are calorie-dense, completely oil-free diets may lead to inadequate satiety and greater blood sugar fluctuations. For most adults, about 2-3 tablespoons daily is reasonable, with at least half from high monounsaturated fat oils.
7. Mind Oil Storage & Shelf Life: Reuse deep-frying oil no more than twice. Prioritize using oils opened for over 3-6 months. Store in a cool, dark place to reduce oxidation and rancidity risk.

Pair Olive Oil with This Fruit for Breakfast

Sit states that while the following 7 methods won't bring immediate reversal in 1-2 weeks, they can help the body gradually stabilize blood lipids, sugar, and inflammation markers over several months:

1. Inventory All Household Oils: List all current oils, noting their primary fatty acid profiles (high mono/polyunsaturated, high saturated). Understand the actual oil types used daily.
2. Designate 1-2 Primary Daily Oils: Select olive and canola oil as main cooking oils, stipulating they be used for over 70% of frying, stir-frying, and stewing.
3. Set a Deep-Frying Limit: If deep-frying at home, set a rule to discard oil after a maximum of 2 uses, without topping up or mixing. Dispose of cooled oil after each use to avoid repeated heating.
4. Schedule 2-3 Omega-3 Rich Dinners Weekly: Examples: baked salmon with olive oil-tossed blanched greens, pan-fried mackerel with brown rice. Those with high triglycerides can discuss fish oil supplementation with their doctor.
5. Transform "Bulletproof Coffee" into a "Bulletproof Breakfast Plate": Move the daily tablespoon of coconut oil from coffee to breakfast by incorporating quality fat sources like avocado with olive oil or nuts with unsweetened yogurt, so saturated fat isn't the sole dietary focus.
6. Practice Keeping an Oil Diary: For 7 consecutive days, simply record daily oil types and approximate amounts. Observe correlations with weight, waist circumference, and lipid changes after three months to build awareness.
7. Review Personal Omega-3 Sources: Reflect on how many meals this week included deep-sea fish or plant-based Omega-3 (e.g., flaxseed, pecans). If zero, start adjusting by incorporating these foods.